Fix memory leak of IdentifierIterator object.

llvm-svn: 118371
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index f0c21f4..65e8659 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -3000,7 +3000,7 @@
       // Walk through identifiers in external identifier sources.
       if (IdentifierInfoLookup *External
                               = Context.Idents.getExternalIdentifierLookup()) {
-        IdentifierIterator *Iter = External->getIdentifiers();
+        llvm::OwningPtr<IdentifierIterator> Iter(External->getIdentifiers());
         do {
           llvm::StringRef Name = Iter->Next();
           if (Name.empty())