Agent state options (report_interval), or interface related options
(f.e. ovs_integration_bridge) should be exposed into all configuration
files for all agents that may report a state, or instantiate a bridge
object.
Since some of options that were previously considered 'base' don't apply
to metering agent (specifically, availability_zone), moved them into
separate lists and included them into relevant agents (l3 and dhcp).
The only glitch with the change is that log_agent_heartbeats option is
now exposed into metering agent configuration file, even though the
agent does not honour it. I think it's minor and we can live with it.
Change-Id: Ibceca20cec60e75a8c6ddd35f3f9cb8cca272a9e
a8e1badbd2