Storm 585

Hello, I just fixed the issue I found : https://issues.apache.org/jira/browse/STORM-585.
I pushed it to my fork, into branch STORM-585.
As this is my first pull request from my fork, I just hope I didn't do anything stupid and that I'm following the process correctly...
Please review the changes; do not hesitate to get back to me :-)
Thanks a lot for your help, and letting me contribute to this great project!!!