StringRefize and take out an old FIXME

llvm-svn: 207962
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 34954a8..54a332a 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -11390,9 +11390,10 @@
       // a tag in front.
       if (const RecordType *RT = T->getAs<RecordType>()) {
         RecordDecl *RD = RT->getDecl();
-      
-        std::string InsertionText = std::string(" ") + RD->getKindName();
-      
+
+        SmallString<16> InsertionText(" ");
+        InsertionText += RD->getKindName();
+
         Diag(TypeRange.getBegin(),
              getLangOpts().CPlusPlus11 ?
                diag::warn_cxx98_compat_unelaborated_friend_type :