Cleanup dependencies for neutron-base

The python-neutron package now pulls the required dependency on
python-oslo-reports:

https://github.com/openstack-packages/neutron/blob/774036f7f99cd54bdd1c94f70d28bfe15f47af83/openstack-neutron.spec#L125

TrivialFix

Change-Id: I6cb4d0d9601c910cf631dddcf715a7f4fc9754e3