git index casing may be wrong

[ctaggart]

I need to revert #158 to fix #167. When core.ignorecase is set to true which is is by default on Windows, the casing of the index returned may be wrong. In the case of Rx.NET, index.Path ended up being a lowercase source directory instead of the valid Source directory.

Notes

https://ci.appveyor.com/project/dotnetfoundation/rx-net-la3iv/build/1.0.141#L653

    file not in git, case does not match Rx.NET\Source\src\System.Reactive\AnonymousObservable.cs, Rx.NET\source\src\System.Reactive\AnonymousObservable.cs, for file AnonymousObservable.cs

https://raw.githubusercontent.com/ctaggart/Rx.NET/024bd242f97d64537fc77cdd1dc7746f1917cc2d/Rx.NET/Source/src/System.Reactive/AnonymousObservable.cs

https://raw.githubusercontent.com/ctaggart/Rx.NET/024bd242f97d64537fc77cdd1dc7746f1917cc2d/Rx.NET/source/src/System.Reactive/AnonymousObservable.cs
404 not found

Here are my unfiltered AppVeyor notes:

      echo "global is"
      git config --global core.ignorecase
      echo "system is"
      git config --system core.ignorecase
      echo "local is"
      git config --local core.ignorecase
      echo "set it to false"
      git config core.ignorecase false
      # git config --unset-all core.ignorecase
      echo "get it"
      git config core.ignorecase

global is
system is
local is
true
set it to false
get it
false