Free parent and ref in lg2_commit before returning.

examples/commit.c

@@ -79,6 +79,8 @@ int lg2_commit(git_repository *repo, int argc, char **argv)
 	git_index_free(index);
 	git_signature_free(signature);
 	git_tree_free(tree);
+	git_object_free(parent);
+	git_reference_free(ref);
 
 	return error;
 }