[objc-arc] Changed 'mode: c++' => 'C++' at Nick Lewycky's suggestion. Also removed unnecessary mode: c++ lines from .cpp files.

llvm-svn: 186026
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCAliasAnalysis.h b/llvm/lib/Transforms/ObjCARC/ObjCARCAliasAnalysis.h
index 7abe995..41ccfe2 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCAliasAnalysis.h
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCAliasAnalysis.h
@@ -1,4 +1,4 @@
-//===- ObjCARCAliasAnalysis.h - ObjC ARC Optimization -*- mode: c++ -*-----===//
+//===- ObjCARCAliasAnalysis.h - ObjC ARC Optimization -*- C++ -*-----------===//
 //
 //                     The LLVM Compiler Infrastructure
 //