[Objective-C Sema]. Warn when an indirectly overridden property
mismatches the one declared in current class; in addition to
those that are directly overridden. 
// rdar://15967517


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201446 91177308-0d34-0410-b5e6-96231b3b80d8