The show command currently just dumps the entire attachments
dictionary into the output which is a real mess and completely
screws up the displayed output (shell command).

There's really no reason to do this, we can just give the
attachment ID's and then when you're on the newer versions
you can do an attachment-show for all the crazy details if
you want.  Keep in mind that the list command already shows
the server-id we're attached too, but that might also be
nice from the show command rather than jumping through
multiple commands.  To try and accomodate various use cases
we'll also add an "attached_servers" field to the show command,
but you'll have to coorelate manually from there.

Change-Id: I45ac49d8d9a185c52727c5bc24a6a1323be83689
Closes-Bug: #1494941

The behaviour of PY3's standard lib 'argparse'
differs from PY2's.

```
cinder extend 2
usage: cinder extend <volume> <new_size>
error: too few arguments
Try 'cinder help extend' for more information.

cinder extend 3
usage: cinder extend <volume> <new_size>
error: the following arguments are required: <new_size>
Try 'cinder help extend' for more information.

```
This could lead to the partly failure of functional testcase,
fix it.

Change-Id: I59e9ae149af0b4294b09a94a52a4bc86a1d90f2b
Closes-Bug: #1697428

Use 'six.text_type' to wrap defined string value.

Change-Id: I229d58595494f59f03538be79de42f2e8007f442
Closes-Bug: #1697401

There are some PEP8 errors that are not caught by our gate because of
the pep8 package version installed by hacking.

This patch fixes E402, W503, and F999 erors from our codebase.

Change-Id: I0b86730b1493f161645a87c3daa91ec3d774d3b1

Change-Id: Icec43c572e43eccc0408667877329bedf0f2fc1a

LVM driver doesn't support mulltiattach now. That's why this test fails
on gates. We have to disable it until multiattach will be supported.

Change-Id: I690982dfa81a566d1632ebe81c54f5596316b02f