Fix duplicate declaration of neutron_tunnel firewall rule

If we have more than one network node we have to ensure firewall
rules are generated with not only host but also destination ip in
name.

Change-Id: I6c990fe301731078ddfa42de9552a591336b6788
Resolves: rhbz#1174001
(cherry picked from commit e07307b436420490a4cd4df1d85d1143cf8b0e5f)