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/Serialization/ASTReaderStmt.cpp b/lib/Serialization/ASTReaderStmt.cpp
index 24da01a..4292b0f 100644
--- a/lib/Serialization/ASTReaderStmt.cpp
+++ b/lib/Serialization/ASTReaderStmt.cpp
@@ -382,7 +382,7 @@
   bool isPascal = Record[Idx++];
 
   // Read string data
-  llvm::SmallString<16> Str(&Record[Idx], &Record[Idx] + Len);
+  SmallString<16> Str(&Record[Idx], &Record[Idx] + Len);
   E->setString(Reader.getContext(), Str.str(), kind, isPascal);
   Idx += Len;