These two options are set in neutron-api charm centrally,
this patch allows neutron-gateway charm to continue doing:
1, rpc_response_timeout
Used by all neutron agents, so both neutron-gateway charm and
neutron-openvswitch charm get it via it's relations and set it
in [default] of neutron.conf
2, report_interval
Used by all neutron agents, so both neutron-gateway charm and
neutron-openvswitch charm get it via it's relations and set it
in [agent] of neutron.conf
This patch also syncs charmhelpers for setting them centrally.
Change-Id: Ib97418b1aaf55f508cae05f4d7809d79a92a7f6f
Partial-Bug: #1685788
d49b2a18ee