The OVS Firewall has a singleton class that manages the conjuction IDs
to used in the OF rules. Those conjuntions are used to group rules
related to remote security group IDs.
Now each time the OVS agent is started, the OVS Firewall initial
conjunction ID is calculated based on the present OF rules. This value
and the next one used won't clash with any present rule in the
integration bridge during the initial transient period.
Related-Bug: #1934917
Change-Id: Ie2e4441f766947a2164dec2d1555c7049428903f
0634dcc6d0