Make unhandled exceptions not fatal

This commit removes a raise in the server class when it encounters an
unhandled exception. Previously the exception would be logged and then
it would raise it again, which would be fatal to the process. We
encountered a DB connection issue a few weeks ago which shouldn't be
fatal to the worker (just that one event/db connection) but this
crashed the worker process. So this attempts to remedy this from
happening in the future by not making this sort of failure fatal to
the whole process.

Maybe this isn't a good idea, but since the first time we encountered
an unhandled exception being raised in the server class it brought
down the worker for ~22 days. So the thought is instead of crashing
just logging the failure and moving on is a better idea. However,
if there is really a fatal exception being raised this means the
process will never crash and just log it on each event.

Change-Id: I4019831e24144205508f7918dab5c8fce6cfc74a

files/subunit-gearman-worker.py

@@ -239,7 +239,6 @@ class Server(object):
                 self.processor.handle_subunit_event()
             except:
                 logging.exception("Exception processing log event.")
-                raise
 
 
 def main():