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/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp b/lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp
index 23c53d2..6005ecd 100644
--- a/lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp
@@ -146,7 +146,7 @@
 
       StringRef DstName = getPrintableName(DstArg);
 
-      llvm::SmallString<256> S;
+      SmallString<256> S;
       llvm::raw_svector_ostream os(S);
       os << "Potential buffer overflow. ";
       if (!DstName.empty()) {