Objective-C modern rewriter. Patch to fix a rewriting bug 
rewriting an Objective-C block. Patch by Ryan Govostes.
rdar://18799145 


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@220834 91177308-0d34-0410-b5e6-96231b3b80d8