change port status only if port is bound to the good host

if host is set in the rpc message update_device_up/down sent by the agent,
the port status will be changed only if the port is bound to the host.

Change-Id: I0e607c734fbebf0b69f83c3bbd3e25a9783672dc
Closes-Bug: #1224967
Merge "change port status only if port is bound to the good host"