ipkg sourcedir can't be more than 1 level deep

[shmish111]

If your source code is in src/sub and you add sourcedir = "src/sub" you will get unexpected '"' or with sourcedir = src/sub you will get unexpected '/'

Steps to Reproduce

Create a module called Main.idr in the directory issue/src

module Main

main : IO ()
main = pure ()

Create issue.ipkg in the parent directory of issue/src

package issue

modules = Main

sourcedir = idris/issue

run idris --build issue.ipkg

Expected Behavior

compilation completes

Observed Behavior

idris fails to parse ipkg file