Neutron already takes care of the HA for dhcp agents. See neutron setting
`dhcp_agents_per_network` in `neutron.conf`. Having the OCF script call dhcp
replication function of neutron-ha-tool would mean that the tool will
try to plug each network to each DHCP agent, which contradicts neutron's
settings.
Change-Id: I87d9f7010092178c1677e14456b5e2606e5830dc