NSXv3: Error returned when tenant creates router with --distributed attribute

When a tenant create a distributed router explicitly with --distributed option, plugin returns general error saying "unrecognized attribute". I think in NSXv3, when a tenant create a logical router, by default it is a distributed router. We should either support the --distributed attribute, or we should be more meaningful error.

stack@htb-1n-eng-dhcp8:/opt/stack/tempest$ neutron router-create dvr --distributed True
Unrecognized attribute(s) 'distributed'

neutron log
2016-01-06 23:18:37.824 DEBUG neutron.api.v2.base [req-42406f4d-6082-4845-924b-b1c4eba0c429 demo fb5e19c3bd5349bf8d2fa2590dd20f46] Request body: {u'router': {u'distributed': u'True', u'name': u'dvr', u'admin_state_up': True}} from (pid=8415) prepare_request_body /opt/stack/neutron/neutron/api/v2/base.py:645
2016-01-06 23:18:37.824 INFO neutron.api.v2.resource [req-42406f4d-6082-4845-924b-b1c4eba0c429 demo fb5e19c3bd5349bf8d2fa2590dd20f46] create failed (client error): Unrecognized attribute(s) 'distributed'