Enable configurtion of contrail extensions
Set the default value of contrail_extensions as per the review comment
Add Quota Support

Implement QuotaDriver based on neutron.ConfDriver

Signed-off-by: Nicolas PLANEL <nicolas.planel@enovance.com>
Fix bug when attempt to create fip in a private net

This commit fixes an Exception when user tries to create a
floating ip on a no-external network.

Closes-Bug: 1322185
Signed-off-by: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@cloudwatt.com>
Bug 1326969: fix issues in get_ports and get_floatingips
setting gw to first+1 if gw_ip is not given in subnet_create, fixed dns_nameserver display issue in subnet_vnc_to_neutron()
Fixed the wrong ContrailPlugin import path in quota driver