Fix a typo in the function name that I just introduced (r201155)


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@201156 91177308-0d34-0410-b5e6-96231b3b80d8
Rename some PCH-related errors to have 'err_' as their prefix


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@201157 91177308-0d34-0410-b5e6-96231b3b80d8