l3_odl: put request for remove_interface, not delete
l3_odl: put request for remove_interface, not delete

remove_interface requires PUT method, not DELETE method.
Thus remove_interface results in internal server error.

Closes-Bug: #1485800
Change-Id: I9c1b6efc8343cc5256dcaa7a35c5c9771fa98479

CiscoSystems/networking-odl,schoksey/networking-odl,flavio-fernandes/networking-odl,FedericoRessi/networking-odl,openstack/networking-odl,CiscoSystems/networking-odl,schoksey/networking-odl,flavio-fernandes/networking-odl,FedericoRessi/networking-odl,openstack/networking-odl,openstack/networking-odl