Fix windows' implementation of status when a file doesn't exist.

The unix one was returning no_such_file_or_directory, but the windows one
was return success.

Update the one one caller that was depending on the old behavior.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187463 91177308-0d34-0410-b5e6-96231b3b80d8