Compiler files in Roslyn.Compilers.Extension.vsix are unsigned, causing Signed build break

[agocke]

Relevant output from SignCop:

* Unsigned : 4
     Roslyn.Compilers.Extension.vsix\csc.exe
     Roslyn.Compilers.Extension.vsix\Microsoft.Build.Tasks.CodeAnalysis.dll
     Roslyn.Compilers.Extension.vsix\vbc.exe
     Roslyn.Compilers.Extension.vsix\VBCSCompiler.exe

[jasonmalinowski]

This was fixed last night.