Fix PolicyException on restarting service
Fix PolicyException on restarting service

Current behaviour allows to create two tables with multiple arities
if one of the arity is 0. But loading the same rules
on restarting the service fails. This commit is to fix the same.

Change-Id: I133532658c421d09640419cef7857cf5eaa864d9
Closes-Bug:#1515890

ramineni/my_congress,openstack/congress,ramineni/my_congress,ramineni/my_congress,ramineni/my_congress,openstack/congress