ONOS-2896 Updating onos.conf for onos-package
ONOS-2896 Updating onos.conf for onos-package

Adding pre-start script to ensure that /opt/onos/{var,config,log} are present, and
create them if they are missing

Also, prefill the user and options if /opt/onos/options is missing

Change-Id: Iae0ed182435669d2247c46929e3df5a18dd0aac5

packet-tracker/onos,packet-tracker/onos,packet-tracker/onos,packet-tracker/onos