Comment 7 for bug 1417312

The fix for bug 1416177 has been back-ported, and should resolve the null subnet part of this issue.

I'm not convinced we should block attempts to create any L3 policy whose ip_pool overlaps the default L3P ip_pool attribute value. Its really up to the user whether they want to use default L3Ps at all, and if so, what CIDR they use. I expect tenants will either use implicit or explicit L3P creation, and not try to mix these. If the user creates an L3P that overlaps the default CIDR, and then wants to use implicit L2P creation when creating PTGs, they can explicitly create an L3P named 'default' that uses a different CIDR, and then this L3P will be used for implicit L2Ps for subsequent PTGs.

I do kind of agree we should reduce the default ip_pool value from a /8 to maybe a /16. In doing so, we could also pick something other than 10.0.0.0/16 to reduce the chance of previous explicitly-created L3Ps colliding with default L3P creation.