Bug: 2688
This bug deals with migrating data when upgrade happens. This fix
initially takes care of 1.3-1.4 data upgrade required. It moves the contents
of the old index table in 1.3 to the new index table in 1.4
Run over each row-key in the index table.Lookup for the flow info in the
FlowRecord table and insert the information in the new table. After
update truncate the old tables.
The db-utils take oldversion as its argument and runs through a chain of
upgrade functions to move the data.
Merge pull request #591 from praveenkv/master

Minor code restrucutre
Removing a redundant declaration
Changes to check for wrong version number as input
Get the version from contrail-analytics-venv
Merge pull request #589 from Juniper/arvindv-upgrade_script

Bug: 2688
Test subscribe/unsubscribe to two different incarnations of instance.

The first subscribe/unsubscribe are processed after the table has been
marked as deleted but has not yet been destroyed. The second subscribe
is received before the table and instance have been destroyed. Later,
the old table and instance are destroyed and new incarnations created.
The subscribe needs to happen on the new incarnation.
Merge pull request #592 from Juniper/nsheth_xmpp_deferq

Test subscribe/unsubscribe to two different incarnations of instance.