systemvm: change vrrp multicast address

- For some reason 224.0.0.x doesn't work over the GRE tunnels. Switched
  to 225.0.0.50 (already firewall rules in places). Maybe it would have
been clearer to use a different address and also patch the firewall
rules.

Author: Johan Mårtensson

systemvm/patches/debian/config/opt/cloud/templates/keepalived.conf.templ

@@ -17,6 +17,7 @@
 
 global_defs {
    router_id [ROUTER_ID]
+   vrrp_mcast_group4 225.0.0.50
 }
 
 vrrp_script heartbeat {
@@ -48,4 +49,4 @@ vrrp_instance inside_network {
     notify_backup "/opt/cloud/bin/master.py --backup"
     notify_master "/opt/cloud/bin/master.py --master"
     notify_fault "/opt/cloud/bin/master.py --fault"
-}
+}