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/DereferenceChecker.cpp b/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
index ed04f86..7e4761c 100644
--- a/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
@@ -108,7 +108,7 @@
       if (!BT_null)
         BT_null.reset(new BuiltinBug("Dereference of null pointer"));
 
-      llvm::SmallString<100> buf;
+      SmallString<100> buf;
       SmallVector<SourceRange, 2> Ranges;
       
       // Walk through lvalue casts to get the original expression