Include cisco plugin in migration plugins with ovs

Currently we have many migration files with missing cisco
plugin in migrate_plugin when ovs is included.This
causes missing tables when cisco plugin is enabled
and migration is run. This fix should automatically
include the cisco plugin if ovs is detected in the
migrate_plugins.

Change-Id: I4dedfbafe9b431e85255d5427766e22eed09ee5e
Closes-Bug: #1292114
(cherry-picked from f23d081b26071e1b309f49e5a5ab0cdc1a739e9d )
Change report_interval from 4 to 30, agent_down_time from 9 to 75

report_interval is how often an agent sends out a heartbeat to the
service. The Neutron service responds to these 'report_state' RPC
messages by updating the agent's heartbeat DB record.
The last heartbeat is then compared to the configured
agent_down_time to determine if the agent is up or down.
The agent's status is used when scheduling networks on DHCP
and L3 agents.

In the spirit of sane defaults suited for production, these values
should be bumped to reduce the load on the Neutron service
dramatically, freeing up CPU time to perform intensive operations.

DocImpact
Closes-Bug: #1293083

(cherry picked from commit e13d19cab384a9f5f8a00436ad39118f342af32c)
Change-Id: I77bcf8f66f74ba55513c989caead1f96c92b9832
Conflicts:
	neutron/agent/common/config.py
Merge "Change report_interval from 4 to 30, agent_down_time from 9 to 75" into stable/havana
Merge "Include cisco plugin in migration plugins with ovs" into stable/havana