Reconciliation with 10 switches and 1K flows/groups is not stable

This can be tracked here:

https://jenkins.opendaylight.org/releng/view/openflowplugin/job/openflowplugin-csit-1node-flow-services-only-boron/

Basically recovering topology and flows/groups after switch/controller restart has never been very stable in boron but this patch seemed to fix the problem:

https://git.opendaylight.org/gerrit/#/c/53545/

Unfortunately we had to revert the patch for performance reasons.

BR/Luis