fix deletion of related firewall rules

Author: bernardodemarco

server/src/main/java/com/cloud/network/lb/LoadBalancingRulesManagerImpl.java

@@ -2684,7 +2684,12 @@ public LoadBalancerVO findLbByStickinessId(long stickinessPolicyId) {
 
     @Override
     public void removeLBRule(LoadBalancer rule) {
-        // remove the rule
+        FirewallRule relatedFirewallRule = _firewallDao.findByRelatedId(rule.getId());
+        if (relatedFirewallRule != null) {
+            logger.debug("Load balancer [{}] has a related firewall rule [{}]. Removing it.", rule.getUuid(), relatedFirewallRule.getUuid());
+            _firewallDao.remove(relatedFirewallRule.getId());
+        }
+
         _lbDao.remove(rule.getId());
     }