Exits process when encountered by a database exception

Database errors could mean database node failure. In this cases, the process
should exit so it could be automatically restarted (when handled by Docker Swarm, K8s, etc)
so it can obtain a new DB connection to an alive node.

Change-Id: I42a3954fe238a0445101eb71add79aaef4315c2e
Signed-off-by: Benjamin Diaz <bdiaz@whitestack.com>