Add a module test for the failover table

This change intends to introduce a place for module testing the
failover log. It is not intended to be a complete set of tests.

Change-Id: I75dabff76547f9d090870fabae9cacaee773db16
Reviewed-on: http://review.couchbase.org/36729
Reviewed-by: abhinav dangeti <abhinav@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>