Security group rule list doesn't show IPv6 addresses

While looking at a neutron security group rule issue, I added a bunch of random IPv4 and IPv6 rules. But when I looked at them I couldn't tell some apart:

$ openstack security group rule list default
+--------------------------------------+-------------+-----------+------------+--------------------------------------+
| ID | IP Protocol | IP Range | Port Range | Remote Security Group |
+--------------------------------------+-------------+-----------+------------+--------------------------------------+
| 0d419c93-49e0-483e-b9e3-5519e87e4e9e | 89 | 0.0.0.0/0 | | None |
| 1457b3aa-0b75-4dbd-a8cb-7111c7bc9832 | tcp | None | 22:22 | None |
| 22625b22-d02c-4e55-9fdb-1c1fb0fdda3d | 99 | 0.0.0.0/0 | | None |
| 228c39b7-6d64-46b6-b10e-6a73a89409af | None | None | | 341d35f2-b931-494c-a6b4-f0b880d2cc05 |
| 395cae51-3ab7-46b4-89f8-690b0536f53b | 6 | 0.0.0.0/0 | 101:101 | None |
| 4d25aa31-a5c5-4bde-9d05-a8a54da20514 | icmp | 0.0.0.0/0 | | None |
| 77d2d543-f969-4d28-a990-6d7c01b14cd7 | None | None | | None |
| 86d35c45-d3d5-42ef-a896-9d6bd5c10440 | None | None | | None |
| b056e0bb-97e7-4088-983f-418625e84caf | icmp | None | | None |
| c5f378a2-8747-4c39-9639-00c3d984a6fe | None | None | | 341d35f2-b931-494c-a6b4-f0b880d2cc05 |
| ce1d14da-8e9e-4a3c-8ca1-e5dc296bb454 | tcp | 0.0.0.0/0 | 22:22 | None |
| cf5a879a-6a57-4a06-bf14-1a14a7100147 | 98 | None | | None |
| fddcb62b-e5a6-436e-ba81-43782c175708 | 98 | 0.0.0.0/0 | | None |
+--------------------------------------+-------------+-----------+------------+--------------------------------------+

There is a couple of improvements I think we can make:

1. Print "::/0" instead of None when the ethertype is IPv6, it only does this for IPv4 currently.

2. Always print the ethertype, which is currently only done with --long.

I'll send out a review.