If there is no flow, QOS configuration should come from interface
If there is no flow, QOS configuration should come from interface

The QOS configuration value from flow was always taken even if there
was no valid value in the flow.

Change-Id: I0ab874744257318bd90f11263e34dfe5e4b6307d
Closes-BUG: #1598772

codilime/contrail-vrouter,codilime/contrail-vrouter,codilime/contrail-vrouter,codilime/contrail-vrouter