Syncing R2.2 instance manager changes
Syncing R2.2 instance manager changes

These changes are missing in mainline which are present in R2.2.
In particular, when a task times out or if error is found while
executing the task, service instance need not be unregistered.
Scheduleing of the next task takes care of handling the events.

Change-Id: I1a44b055fea3fbb475529783c8806b0cc74ed7a0
closes-bug: #1480082

hthompson6/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,sajuptpm/contrail-controller,tcpcloud/contrail-controller,reiaaoyama/contrail-controller,nischalsheth/contrail-controller,sajuptpm/contrail-controller,rombie/contrail-controller,facetothefate/contrail-controller,sajuptpm/contrail-controller,rombie/contrail-controller,hthompson6/contrail-controller,reiaaoyama/contrail-controller,vmahuli/contrail-controller,reiaaoyama/contrail-controller,codilime/contrail-controller,rombie/contrail-controller,codilime/contrail-controller,hthompson6/contrail-controller,facetothefate/contrail-controller,vmahuli/contrail-controller,eonpatapon/contrail-controller,codilime/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,facetothefate/contrail-controller,eonpatapon/contrail-controller,codilime/contrail-controller,numansiddique/contrail-controller,numansiddique/contrail-controller,nischalsheth/contrail-controller,vmahuli/contrail-controller,tcpcloud/contrail-controller,nischalsheth/contrail-controller,tcpcloud/contrail-controller,hthompson6/contrail-controller,nischalsheth/contrail-controller,tcpcloud/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,facetothefate/contrail-controller,numansiddique/contrail-controller,numansiddique/contrail-controller,hthompson6/contrail-controller,vmahuli/contrail-controller,codilime/contrail-controller,reiaaoyama/contrail-controller,numansiddique/contrail-controller,tcpcloud/contrail-controller,sajuptpm/contrail-controller,tcpcloud/contrail-controller,sajuptpm/contrail-controller,eonpatapon/contrail-controller,sajuptpm/contrail-controller,rombie/contrail-controller,vmahuli/contrail-controller,eonpatapon/contrail-controller,facetothefate/contrail-controller,eonpatapon/contrail-controller,reiaaoyama/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,codilime/contrail-controller