service-list command display an invalid colomn 'disabled'

[yanzhiwei]

The subcommand 'service-list' display like:
# magnum service-list
+----+--------+------------------+-------+----------+-----------------+---------------------------+---------------------------+
| id | host | binary | state | disabled | disabled_reason | created_at | updated_at |
+----+--------+------------------+-------+----------+-----------------+---------------------------+---------------------------+
| 1 | test112 | magnum-conductor | up | | - | 2017-05-03T06:24:44+00:00 | 2017-06-05T01:44:47+00:00 |
+----+--------+------------------+-------+----------+-----------------+---------------------------+---------------------------+
the response body doesn't include the information about 'disabled', so we could remove it.