Objective-C [qoi]: Provide improved parse diagnostics when
closing rbrace is missing in an ObjC class declaration.
Can do beter than this, but it involves addition of
overhead which will be present in correct code.
// rdar://6854840


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@177435 91177308-0d34-0410-b5e6-96231b3b80d8