Turn on sandesh local logging and recover on re-established conn

This diff ensures api-server recovers on a re-established conn to
IFMAP + Cassandra and log on edges of lost + re-established connection
to IFMAP, Cassandra, RabbitMQ and Zookeeper.
Also try with retry_count on 503 and raise timeout on 504 in the
client library.

Change-Id: I14723d8c67fd5677e3043074013bda7657dfa5a5
Merge "Turn on sandesh local logging and recover on re-established conn"