[rbslack] Don't cause a 500 if notification fails.
Review Request #6354 — Created Sept. 21, 2014 and submitted
In the case where something fails when trying to send to the slack.com webhook, we shouldn't show the user an error 500. This change catches all exceptions and logs them.
Tool: PEP8 Style Checker Processed Files: rbslack/rbslack/extension.py Tool: Pyflakes Processed Files: rbslack/rbslack/extension.py