nis: Fix a memory leak in nis_creategroup when malloc fails

The zo_domain field was missing from the list of fields to be freed.

Reviewed-by: DJ Delorie <dj@redhat.com>

nis/nis_creategroup.c

@@ -60,6 +60,7 @@ nis_creategroup (const_nis_name group, unsigned int flags)
 	  free (obj->zo_group);
 	  free (obj->zo_owner);
 	  free (obj->zo_name);
+	  free (obj->zo_domain);
 	  free (obj);
 	  return NIS_NOMEMORY;
 	}