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/Sema/SemaObjCProperty.cpp b/lib/Sema/SemaObjCProperty.cpp
index 0293527..f9c064d 100644
--- a/lib/Sema/SemaObjCProperty.cpp
+++ b/lib/Sema/SemaObjCProperty.cpp
@@ -1341,7 +1341,7 @@
 
 static IdentifierInfo * getDefaultSynthIvarName(ObjCPropertyDecl *Prop,
                                                 ASTContext &Ctx) {
-  llvm::SmallString<128> ivarName;
+  SmallString<128> ivarName;
   {
     llvm::raw_svector_ostream os(ivarName);
     os << '_' << Prop->getIdentifier()->getName();