servicerouter: add option to disable logging to syslog
servicerouter: add option to disable logging to syslog

mesosphere/marathon-lb,JamesAwesome/marathon-lb,GrovoLearning/marathon-lb,matt-deboer/marathon-lb,GrovoLearning/marathon-lb,mesosphere/marathon-lb,JamesAwesome/marathon-lb,mesosphere/marathon-lb,matt-deboer/marathon-lb,knesenko/marathon-lb,GrovoLearning/marathon-lb,vixns/marathon-lb,vixns/marathon-lb,vixns/marathon-lb,JamesAwesome/marathon-lb,knesenko/marathon-lb,knesenko/marathon-lb,matt-deboer/marathon-lb