When floating IP or port with DNS records are created and the recordset
quota value of the external dns service (e.g. designate) exceeds limit,
the recordset creation fails. Report the exact reason of failure i.e.
ExternalDNSOverQuota instead of HttpException.
Depends-On: https://review.opendev.org/c/openstack/neutron-lib/+/786174
Closes-Bug: #1923700
Change-Id: Ie1dd5c26ec0eb1875d2a6a176838598117678f4a