Couldn't get package details for nuget pkg with dash in name in local source

[Bomret]

With a local nuget source (Dir in repo) and a package with a dash in the name (rx-core) Paket fails with:

Resolving packages:
    - exploring Rx-Core 2.1.30214.0
Paket failed with:
    Couldn't get package details for package Rx-Core on ["./nugets"]

StackTrace:
     bei [email protected](String message)
   bei Paket.NuGetV2.tryNext@433(Boolean force, FSharpList`1 sources, SemVerInfo version, String activePatternResult, FSharpList`1 xs)
   bei Paket.NuGetV2.GetPackageDetails(Boolean force, FSharpList`1 sources, PackageName _arg1, SemVerInfo version)
   bei Paket.PackageResolver.getExploredPackage@96(FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, FSharpList`1 sources, PackageName packageName, SemVerInfo version, FSharpList`1 frameworkRequirement)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei [email protected](SemVerInfo versionToExplore)
   bei Microsoft.FSharp.Collections.ListModule.loop@142-20[T,TState](FSharpFunc`3 f, TState s, FSharpList`1 xs)
   bei Paket.PackageResolver.improveModel@143(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, Dictionary`2 exploredPackages, Dictionary`2 allVersions, FSharpMap`2 filteredVersions, FSharpList`1 packages, FSharpSet`1 closed, FSharpSet`1 stillOpen)
   bei Paket.PackageResolver.Resolve(FSharpFunc`2 getVersionsF, FSharpFunc`2 getPackageDetailsF, FSharpList`1 rootDependencies)
   bei Paket.DependenciesFile.Resolve(FSharpFunc`2 getSha1, FSharpFunc`2 getVersionF, FSharpFunc`2 getPackageDetailsF)
   bei Paket.UpdateProcess.SelectiveUpdate(DependenciesFile dependenciesFile, FSharpOption`1 exclude, Boolean force)
   bei <StartupCode$Paket-Core>[email protected](Unit unitVar0)
   bei Paket.Utils.RunInLockedAccessMode[a](String rootFolder, FSharpFunc`2 action)
   bei [email protected](Unit unitVar)
   bei <StartupCode$paket>.$Paket.Program.main@()

This works when using the official nuget api.

I managed to create a minimalist demo here:
https://github.com/Bomret/Paket_issue_demos/tree/master/issue_556