VS integration: use the correct registry key after r195379

I changed the registry key in that commit, but forgot to update
the integration files. This change makes them use the same variable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195479 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed