There are use cases where instances on the subnet need to access
one another via floating IP's. For this to work, we need to create
the NAT rules on the internal interfaces of the edge.
Before this change, floating IP NAT rule was added to external
interface only, and hosts residing on same network were not able
to connect via floating IPs. This behavior is still available
by setting config variable bind_floatingip_to_all_interfaces
to false. New behavior is dependant on driver version:
before 6.2.4, a NAT rule is created explicitly for each vnic
from 6.2.4 onwards, single NAT rule without vnic is created, which
is interpreted by platform as 'bind to all interfaces'.
Change-Id: Iacc858f726f58d05fa54a723304193f3dc1fb66d
4da2726593