Turn off debug for jetty
Turn off debug for jetty

Summary:
The debug logs for jetty are almost never helpful; this reduces noise
significantly when turning on marathon debug logging.

Test Plan: n/a

Reviewers: jdef, jasongilanfarr

Reviewed By: jdef, jasongilanfarr

Subscribers: jenkins, marathon-team

Differential Revision: https://phabricator.mesosphere.com/D300

mesosphere/marathon,guenter/marathon,meln1k/marathon,janisz/marathon,gsantovena/marathon,Caerostris/marathon,mesosphere/marathon,guenter/marathon,gsantovena/marathon,natemurthy/marathon,Caerostris/marathon,meln1k/marathon,Caerostris/marathon,janisz/marathon,mesosphere/marathon,mesosphere/marathon,gsantovena/marathon,guenter/marathon,guenter/marathon,meln1k/marathon,natemurthy/marathon,natemurthy/marathon,Caerostris/marathon,janisz/marathon,gsantovena/marathon,meln1k/marathon,Caerostris/marathon,gsantovena/marathon,mesosphere/marathon,janisz/marathon,guenter/marathon,meln1k/marathon,janisz/marathon