The pylint job was switched over to run under python 3, but
the job is not voting and it was apparently missed that the
conversion was causing it to fail.

This updates the version of pylint to one that is actually
supported by python 3 and makes tweaks to our script to
for the minor changes between versions.

Single character change to get rid of the more strict py3
regex string escape character format.

Change-Id: I93124b62c5ee177815457b32f55f5453fc3d387e
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

Introduce new command 'list-filters' to retrieve
enabled resource filters.

```
command: cinder list-filters --resource=volume

output:
+----------------+-------------------------------+
| Resource       | Filters                       |
+----------------+-------------------------------+
| volume         | name, status, image_metadata  |
+----------------+-------------------------------+

```

Also Added new option '--filters' to these list commands:
1. list
2. snapshot-list
3. backup-list
4. attachment-list
5. message-list
6. group-list
7. group-snapshot-list
8. get-pools

Change-Id: I062e6227342ea0d940a8333e84014969c33b49df
Partial: blueprint generalized-filtering-for-cinder-list-resource
Depends-On: 04bd22c1eb371805a3ce9f6c8915325bc0da2d36
Depends-On: 7fdc4688fea373afb85d929e649d311568d1855a

Following OpenStack Style Guidelines:
http://docs.openstack.org/developer/hacking/#dictionaries-lists
It is not clear as using explicit dictionaries
and help avoid some errors during refactoring.

Change-Id: If29fa568b757e8e08ec2bd8986d08e422db9eee4

Run pylint with
 $ tox -e pylint

(Copied from Cinder with minor changes.)

Change-Id: I9d7f03c44c6da7515b433d6c87f3a1645184d491