Basic: import SmallString<> into clang namespace

(I was going to fix the TODO about DenseMap too, but
that would break self-host right now. See PR11922.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149799 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Rewrite/Rewriter.cpp b/lib/Rewrite/Rewriter.cpp
index 3e1fd20..43fb01b 100644
--- a/lib/Rewrite/Rewriter.cpp
+++ b/lib/Rewrite/Rewriter.cpp
@@ -236,7 +236,7 @@
   FileID FID;
   unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
 
-  llvm::SmallString<128> indentedStr;
+  SmallString<128> indentedStr;
   if (indentNewLines && Str.find('\n') != StringRef::npos) {
     StringRef MB = SourceMgr->getBufferData(FID);