Test to check if a controller is alive.
Test to check if a controller is alive.

To check if controller is up and running, create a socket and try to
connect it to the listening host and port of the controller. If the
controller is dead, then delete the corresponding entry from RFMonitor
instance.

Signed-off-by: Srijan Mishra <c2c41bdc8170583cc0b29d3ebd2deb0e30f77bb7@gmail.com>

arazmj/RouteFlow,raphaelvrosa/RouteFlow,arazmj/RouteFlow,raphaelvrosa/RouteFlow,arazmj/RouteFlow,c3m3gyanesh/RouteFlow-OpenConfig,raphaelvrosa/RouteFlow,c3m3gyanesh/RouteFlow-OpenConfig,srijanmishra/RouteFlow,routeflow/RouteFlow,ralph-mikera/RouteFlow-1,routeflow/RouteFlow,ralph-mikera/RouteFlow-1,c3m3gyanesh/RouteFlow-OpenConfig,routeflow/RouteFlow,c3m3gyanesh/RouteFlow-OpenConfig,routeflow/RouteFlow,c3m3gyanesh/RouteFlow-OpenConfig,srijanmishra/RouteFlow,ralph-mikera/RouteFlow-1,arazmj/RouteFlow,raphaelvrosa/RouteFlow,srijanmishra/RouteFlow,ralph-mikera/RouteFlow-1,ralph-mikera/RouteFlow-1,raphaelvrosa/RouteFlow,srijanmishra/RouteFlow,routeflow/RouteFlow,c3m3gyanesh/RouteFlow-OpenConfig,raphaelvrosa/RouteFlow,arazmj/RouteFlow,arazmj/RouteFlow,ralph-mikera/RouteFlow-1,srijanmishra/RouteFlow