fix space in EVPN driver specification
fix space in EVPN driver specification

Change-Id: I6c8b46874138fd766bf2fc1a7082baef31a03f00

stackforge/networking-bagpipe-l2,openstack/networking-bagpipe-l2,stackforge/networking-bagpipe-l2,openstack/networking-bagpipe,openstack/networking-bagpipe-l2,openstack/networking-bagpipe