Objective-C: merge objc_requires_super attribute of
method declaration into its implementation to
prevent a bogus warning about mismatched attributes.
then make sure the warning about missing call to super comes out
of the method implementation. // rdar://14251387


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185974 91177308-0d34-0410-b5e6-96231b3b80d8