Specify report interval for neutron configuration

Set report interval to 5 seconds which is 3 times
lower than agent_down_time or it may lead to
agent status flapping and neutron server not
communicating with agents

Change-Id: I65dc90df6ea331de624f50ff5da97c46a881b06a
Closes-Bug: #1315338
Merge "Specify report interval for neutron configuration" into stable/4.1