IdentityModel patch to remove commit SHA

[mthalman]

The changes from #198 are causing the following build error when built in the context of a synchronized VMR build leg:

fatal: not a git repository (or any parent up to mount point /)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).

This is related to dotnet/source-build#3573. We can't execute git commands in the build and don't yet have predefined git info we can use.

[eerhardt]

@mthalman are you are going to backport this patch to the identity model repo?

[mthalman]

@mthalman are you are going to backport this patch to the identity model repo?

I wasn't planning on it. It's very much specific to source-build.

[eerhardt]

It's very much specific to source-build.

The whole reason the .sh file is in the repo is because of source-build, isn't it?

[mthalman]

The whole reason the .sh file is in the repo is because of source-build, isn't it?

That was the reason for adding it but that doesn't mean it's not relevant outside of source-build scenarios. It's a Bash version of the existing PowerShell script that does the same thing. Either can be used and should provide the same result.