(1) When Heart beat to the discovery server fails [haproxy down/not started], the discovery client library marks the Discovery connection as DOWN.
However, on successful Heart beat, the connection status is not being marked UP. Also, reset the connection status to DOWN when the response code for
HeartBeat request is not 200.
(2) Increasing the timeout for introspect connection in contrail-status to 0.5 seconds.
In swisscom setup, changing the timeout from 0.01 to 0.1 did not work. Did not see much load on the system. Changing the timeout to 0.5 to be on the safer side.
Closes-Bug: #1372875

Change-Id: I90fa290beac079b25781d5c2ac2db0d5193c0828