contrail-status should indicate ifmap as down if database is empty

[Nischal Sheth]

There are some (not completely understood) failure scenarios where the
ifmap server has an empty database but is published to discovery server
anyway. This leads to hard to diagnose failure modes.

Suggestion is to enhance contrail-status to check if the if map server
at least has a well known object such as the global-system-config or the
global-vrouter-config, and show the status as down if this is not the
case.

If there are issues with credentials etc. perhaps the API server could
check for the well known objects and somehow reflect this in the output
of contrail-status.

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/19554
Submitter: Ranjeet R (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/19554
Committed: http://github.org/Juniper/contrail-controller/commit/f53cc55db960b7c9e6d221d850a23cad64e48b98
Submitter: Zuul
Branch: master

commit f53cc55db960b7c9e6d221d850a23cad64e48b98
Author: rranjeet <email address hidden>
Date: Thu Apr 21 21:57:50 2016 -0700

Fixes: contrail-status should indicate ifmap as down if database is empty

In the health-check for IFMAP, adding a check to check whether the
default global system config is there.

If not publish the IFMAP server as Down with the discovery server
with relevant reason and also bring the ConnectionStatus for IFMAP
in API server to down so that the contrail-status reports that
the IFMAP server connection is not functional.

Change-Id: Ia5c1589055f7795ca4a145403c583588df94cec5
Closes-Bug: 1546689