set port status to PORT_STATUS_ACTIVE if device-id is
specified else PORT_STATUS_DOWN

get contrail:ipam_fq_name from subnet_q only if its present and
not None or ''

Change-Id: I4c852ce72232555350f1e42dbfc9a5391e1f2348
Merge "set port status to PORT_STATUS_ACTIVE if device-id is specified else PORT_STATUS_DOWN"