Fixed an LLVM/Clang assertion that would happen for C++ and ObjC methods if...

Fixed an LLVM/Clang assertion that would happen for C++ and ObjC methods if the DWARF doesn't specify the accessibility for the method. Currently gcc 4.2 and clang++ do not set the accessibility correctly on methods. We currently shouldn't default to private since public methods don't have the accessibility specified. 

Bottom line: we currently default to public for both C++ and ObjC if the accessibility isn't set.

llvm-svn: 115016