Kill cocoa::deriveNamingConvention and cocoa::followsFundamentalRule. They are now...

Kill cocoa::deriveNamingConvention and cocoa::followsFundamentalRule. They are now just simple wrappers around method families, and method decls can cache method family lookups. Also, no one is using them right now.

The one difference between ObjCMethodDecl::getMethodFamily and Selector::getMethodFamily is that the former will do some additional sanity checking, and since CoreFoundation types don't look like Objective-C objects, an otherwise interesting method will get a method family of OMF_None. Future clients that use method families should consider how they want to handle CF types.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153000 91177308-0d34-0410-b5e6-96231b3b80d8