Objective-C. Patch to handle bridge attribute warnings
correctly when both NSAttributedString and
NSMutableAttributedString are specified on the same
CFStruct via different typedefs. // rdar://17238954


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@210660 91177308-0d34-0410-b5e6-96231b3b80d8