Removing some more unnecessary manual quotes from diagnostics. Updated the related test case to ensure correctness.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198412 91177308-0d34-0410-b5e6-96231b3b80d8
Removing an unneeded typecast. getScopeRep() already returns a NestedNameSpecifier.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198413 91177308-0d34-0410-b5e6-96231b3b80d8