Description of problem:
Right now, if a node hosting a gateway router port goes down, the next priority node will take over and host this router.

However, if the node loses the connectivity with the external network, the router won't be failover.


Steps to Reproduce:
1. Remove external connectivity to the node hosting a gw router with highest prio

Actual results:
Check that the router has not been taken over by another node.


Expected results:
The expected behavior is that the next node with highest priority and external connectivity takes over the gw port(s).


Additional info:
It has to be taken into account that if the monitored destination of the external network goes down, the last chassis has to still host the gw port or no node will host the router (needed for VLAN tenant networks for example)