refactor code relating to mesos connector, preparing for framework failover
refactor code relating to mesos connector,
preparing for framework failover

Signed-off-by: kevin xu <b37b7387671111fab980ad3c913a7fb17773b886@gmail.com>

bbklab/swan,xiaods/swan,pwzgorilla/swan,xiaods/swan,Dataman-Cloud/swan,bbklab/swan,pwzgorilla/swan,Dataman-Cloud/swan