Drop neutron-functional job from devstack-gate
The neutron-functional job has been refactored to be a native zuulv3 job
and doesn't use devstack-gate anymore, so no need to continue running it
against devstack-gate patches.
[0]
- neutron-grenade-multinode
- neutron-grenade-dvr-multinode:
voting: false
- - neutron-functional:
- voting: false
- legacy-tempest-dsvm-neutron-full-ocata:
voting: false
- legacy-tempest-dsvm-neutron-full-centos-7:
