Teach Clang parser to reject C++11 attributes that appertain to declaration specifiers.

We don't support any C++11 attributes that appertain to declaration specifiers so reject 
the attributes in parser until we support them; this also conforms to what g++ 4.8 is doing.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@167481 91177308-0d34-0410-b5e6-96231b3b80d8