Add quotas for fixed ips.

DocImpact: there is now a default quota of 10 fixed ips per tenant.
This will need to be adjusted by deployers if that number does not
meet their needs.

Resolves bug 1125468.

Change-Id: Iffa19583340f80cb2a13ba5fce31f7ff724a52d6
Merge "Add quotas for fixed ips."