Fix FileCheck --check-prefix lines.

Various tests had sprung up over the years which had --check-prefix=ABC on the
RUN line, but "CHECK-ABC:" later on. This happened to work before, but was
strictly incorrect. FileCheck is getting stricter soon though.

Patch by Ron Ofir.

llvm-svn: 188174

clang/test/CodeCompletion/using-namespace.cpp

@@ -12,7 +12,7 @@ namespace N2 {
   
   void foo() {
     using namespace
-    // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:14:20 %s -o - | FileCheck -check-prefix=CC1 %s
+    // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:14:20 %s -o - | FileCheck -check-prefix=CHECK-CC1 %s
     // CHECK-CC1: I1
     // CHECK-CC1: I4
     // CHECK-CC1: I5