Update the "neutron" command to "openstack"
Update the "neutron" command to "openstack"

Change-Id: Icfcf7482ee5583020da52fdeff43390c7c2e6961
Implements: blueprint use-openstack-command

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals