remove unneeded llvm:: namespace qualifiers on some core types now that LLVM.h imports
them into the clang namespace.

llvm-svn: 135852
diff --git a/clang/lib/Frontend/FrontendOptions.cpp b/clang/lib/Frontend/FrontendOptions.cpp
index 0a20051..ea4005f 100644
--- a/clang/lib/Frontend/FrontendOptions.cpp
+++ b/clang/lib/Frontend/FrontendOptions.cpp
@@ -11,7 +11,7 @@
 #include "llvm/ADT/StringSwitch.h"
 using namespace clang;
 
-InputKind FrontendOptions::getInputKindForExtension(llvm::StringRef Extension) {
+InputKind FrontendOptions::getInputKindForExtension(StringRef Extension) {
   return llvm::StringSwitch<InputKind>(Extension)
     .Case("ast", IK_AST)
     .Case("c", IK_C)