The no-NAT CIDRs extension is applied to the network resource
in neutron. When applied, it affects the list of subnets that
should be reachable without NAT that are delivered in the RPC
calls to agents. The agents can then use this information to
ensure that specific destination CIDRs will never use NAT.
The extension can be applied to both tenant and external/public
networks. The extension should be used judiciously, as placing
it on a network will cause those CIDRs to be added to all RPC
calls requesting subnets within that VRF (e.g. the extension
could be added to a shared network or to a network that uses
a subnetpool relating to a shared address scope, which would
be seen by all other networks that report to that same address
scope or shared network).
Change-Id: Ic2cdd501933cc21c286ca36218361aadef1878b8
d1ff11cb8e