Fix typo that caused BuildAndCopy.cmd to fail
Fix typo that caused BuildAndCopy.cmd to fail

This fixes CI errors like:

d:\j\workspace\microsoft_msbuild_prtest\CreatePrivateMSBuildEnvironment.proj(33,5): error MSB3021: Unable to copy file "C:\Program Files (x86)\MSBuild\14.0\Bin\amd64\Microsoft.Common.CurrentVersion.targets" to "d:\j\workspace\microsoft_msbuild_prtest\bin\Bootstrap$([System.IO.Path]::DirectorySeparatorChar14.1\Bin\amd64\Microsoft.Common.CurrentVersion.targets". The given path's format is not supported.

chipitsine/msbuild,mono/msbuild,cdmihai/msbuild,Microsoft/msbuild,sean-gilliam/msbuild,mono/msbuild,sean-gilliam/msbuild,Microsoft/msbuild,Microsoft/msbuild,rainersigwald/msbuild,rainersigwald/msbuild,AndyGerlicher/msbuild,sean-gilliam/msbuild,cdmihai/msbuild,cdmihai/msbuild,jeffkl/msbuild,AndyGerlicher/msbuild,rainersigwald/msbuild,Microsoft/msbuild,chipitsine/msbuild,chipitsine/msbuild,cdmihai/msbuild,chipitsine/msbuild,sean-gilliam/msbuild,jeffkl/msbuild,AndyGerlicher/msbuild,AndyGerlicher/msbuild,mono/msbuild,mono/msbuild,jeffkl/msbuild,rainersigwald/msbuild,jeffkl/msbuild