IPTables driver for metering was not handling the DVR router
namespaces properly for configuring the metering forward rules.
This patch addresses the issue by configuring the iptables
manager based on the availability of the namespace and selecting
the respective namespaces such as router namespace and snat
namespace with the right external device.
Closes-Bug: #1506567
(cherry picked from commit ec6ed98cfa)
Conflicts:
neutron/db/metering/metering_db.py
neutron/services/metering/drivers/iptables/iptables_driver.py
Change-Id: I6790d6ff42d9f8fa220e1a231ae94cbf8b60506c
ffcd24a3a8