Add -s option for neutron metering rules

While adding iptables rule, cidr is added as destination for both ingress
and egress directions. Modified code to add -s for egress and -d for ingress.

Closes-bug: 1310589

Change-Id: Id9ca10855e6527d4bec689f8f9bcd6f681221954
Merge "Add -s option for neutron metering rules"