MB-10919: Don't generate new failover entry during vbucket takeover

When a vbucket is transfered from one node to another we should
not generate a new failover entry in the failover log of the
new active vbucket.

Change-Id: I4e9a222ba67fbdb793035544527122e45bf0adc6
Reviewed-on: http://review.couchbase.org/36157
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>