Comment 1 for bug 1475534

So, I've dug into this, and the min/max request for dhcp_agents_per_network for neutron doesn't seem to fit according to the documentation for neutron.conf (which is written from this charm):

http://docs.openstack.org/liberty/config-reference/content/section_networking-options-reference.html

This indicates that there is a single setting "dhcp_agents_per_network" (with a default of 1).

Note that this IS different to the min/max-l3-agents-per-router, which is configured like that in the neutron.conf. See:
http://docs.openstack.org/liberty/config-reference/content/networking-options-l3_agent.html

Therefore, I propose that a single option "dhcp-agents-per-network" is added (with a default of 1).