Sema: Assertion failure during CodeGen in CodeGenModule::EmitUuidofInitializer

Make sure we can properly generate code when the UUID has curly braces
on it, strip the curly braces at the sema layer.

This fixes PR16813.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188061 91177308-0d34-0410-b5e6-96231b3b80d8