Add required extension to trunk_details descriptor
Add required extension to trunk_details descriptor

This was an innocent omission.

Change-Id: I07854a2ed6fdf3ba915957f7a0e2d7a6d32053d8
Related-blueprint: vlan-aware-vms

noironetworks/neutron,sebrandon1/neutron,mahak/neutron,huntxu/neutron,openstack/neutron,sebrandon1/neutron,openstack/neutron,mahak/neutron,eayunstack/neutron,noironetworks/neutron,mahak/neutron,openstack/neutron,cloudbase/neutron,huntxu/neutron,cloudbase/neutron,eayunstack/neutron