Stop abusing StringRef. Fixes the Windows build.

I've also removed the duplicate check for PARSED_ATTR since it seems
unnecessary, and would have made the code more complicated.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158716 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed