remove service-type from neutron extension list
remove service-type from neutron extension list

service-type as an extension is only exposed if neutron advanced
services are enabled because neutron extensions are unlike nova
extensions and aren't directly loaded things, but interfaces that
plugins register that they support.

Change-Id: I6c38bace04070d71b74fa2b18866b3976f2a8524
Closes-Bug: #1491333

LIS/lis-tempest,openstack/tempest,masayukig/tempest,Tesora/tesora-tempest,masayukig/tempest,vedujoshi/tempest,rakeshmi/tempest,openstack/tempest,pczerkas/tempest,izadorozhna/tempest,Juniper/tempest,sebrandon1/tempest,zsoltdudas/lis-tempest,pczerkas/tempest,cisco-openstack/tempest,flyingfish007/tempest,dkalashnik/tempest,izadorozhna/tempest,flyingfish007/tempest,bigswitch/tempest,bigswitch/tempest,sebrandon1/tempest,cisco-openstack/tempest,xbezdick/tempest,xbezdick/tempest,zsoltdudas/lis-tempest,Juniper/tempest,LIS/lis-tempest,Tesora/tesora-tempest,rakeshmi/tempest,vedujoshi/tempest,tonyli71/tempest,tonyli71/tempest,dkalashnik/tempest