Add a missing close quote in "while building module 'Foo:" diagnostic.

This isn't a real diagnostic kind, only a location note, and this form isn't even
used if the SourceManager can provide a valid presumed location. But still.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214002 91177308-0d34-0410-b5e6-96231b3b80d8