Use common is_a_flow_line() method from ovs_lib
Use common is_a_flow_line() method from ovs_lib

Introduced in I16a35b5d6c54901899d24fc94bd3438c1f1be05e

Change-Id: I95d3ff45954dbdb0441b2d58c868108fcf65a454

openstack/networking-sfc,openstack/networking-sfc