Investigate slow-down in DDL after a restart

Todd noticed during testing that if he killed either controllernode or DMLProc, and let it restart, drop table would be occasionally be slow.

Ben reproduced the problem and saw correlation with upstream bandwidth usage. When upstream traffic stops, that's when the drop table stmt would return.
Presumably, SM is sending a lot of data to the cloud, which is blocking the ops for dropping a table.

Ben also couldn't reproduce it when using the 'fake cloud' module.

Need to investigate.