`get_bgp_neighbors`: down neighbors return inconsistent output

[mirceaulinic]

Description of Issue/Question

For down neighbors, the the address family is an empty dictionary:

u'1.2.3.4': {'is_enabled': True, u'uptime': 3981371, 'remote_as': 65500, 'description': u'', 'remote_id': u'', 'local_as': 65000, 'is_up': False, u'address_family': {}