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.)

llvm-svn: 149799
diff --git a/clang/lib/StaticAnalyzer/Checkers/IdempotentOperationChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/IdempotentOperationChecker.cpp
index d77d4d6..df47b04 100644
--- a/clang/lib/StaticAnalyzer/Checkers/IdempotentOperationChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/IdempotentOperationChecker.cpp
@@ -376,7 +376,7 @@
     }
 
     // Select the error message and SourceRanges to report.
-    llvm::SmallString<128> buf;
+    SmallString<128> buf;
     llvm::raw_svector_ostream os(buf);
     bool LHSRelevant = false, RHSRelevant = false;
     switch (A) {