Add missing contants
Add missing contants

Missing constants MIN_VLAN_TAG and MAX_VLAN_TAG in function
is_valid_vlan_tag, path: tacker/common/utils

Change-Id: I26619fa71219c24f2eeed77de3c69e46a00e22a5

openstack/tacker,stackforge/tacker,stackforge/tacker,openstack/tacker,openstack/tacker