devstack: load neutron-northbound-service first
devstack: load neutron-northbound-service first

Load the karaf feature of neutron-northbound-service first as
bug work around of JAXB. [1]
The neutron-northbound-service needs to be loaded before any other JAXB
feature. Otherwise neutron northbound may not work
non-deterministicly. NOTE: Since ODL karaf features are loaded
asynchronously, it's non-deterministic.

[1] https://wiki.opendaylight.org/view/Weather#Neutron_Northbound_must_be_loaded_before_any_other_JAXB_feature

Closes-Bug: #1604642
Change-Id: Ie43d2620aebb043803edc3e24d4397e9ab2c2748

openstack/networking-odl,openstack/networking-odl,openstack/networking-odl