Random temporary string cleanup.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110807 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index fc1418f..77b88f7 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -164,7 +164,7 @@
     llvm::errs() << " [ExpandDisabled]";
   if (Tok.needsCleaning()) {
     const char *Start = SourceMgr.getCharacterData(Tok.getLocation());
-    llvm::errs() << " [UnClean='" << std::string(Start, Start+Tok.getLength())
+    llvm::errs() << " [UnClean='" << llvm::StringRef(Start, Tok.getLength())
                  << "']";
   }