neutron northbound: temporarily disable gbp neutron feature

neutron northbound: temporarily disable gbp neutron feature

This patch is to disable temporarily disable neutron related feature
of group based policy. Once the thing is settled down, this patch
should be reverted.
ODL Neutron Norhtbound projects has revised its yang model which affects
dependent projects[1]. The patch series[2] may break dependent projects
and causes neutron-distribution-check-boron to fail. e.g. [3]
It creates circular dependency of projects so that in order to
make progress, the following process is necessary.

- distribution check needs to be disabled for temporarily(this patch), then
- merge the patches into neutron northbound[2],
- merge fixup patch for group based policy, (and fix other broken projects)
- finally, revert this patch

[1] https://wiki.opendaylight.org/view/Weather#Neutron_Northbound:_neutron_yang_model_revise_and_I.2AAware.28AD-SAL.29_interface_removal
[2] https://git.opendaylight.org/gerrit/#/q/topic:yang-model-revise
[3] https://jenkins.opendaylight.org/releng/job/neutron-distribution-check-boron/214/

Change-Id: Ic600c9a0aea22174ddd221e671e6a1874f0d8fb2
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>