Fixing typo and improving docstring of find_domain

This should make it easier to understand the
purpose of find_domain - I believe the reason
for which find_resource wasn't enough was not
quite clear.

Change-Id: I6a1cdfa86f52401d95c6da2cd38d7c95a140b4a1
Change help text for image save command

Change-Id: Ib2aecb68ffa06f9ac831131944c98c49cf99c75a
Closes-Bug: #1372070
Merge "Fixing typo and improving docstring of find_domain"
Use oslo.utils

Module `importutils` from common code was graduated to oslo.utils,
so it would be great if we reuse this library.
Remove unused strutils.py and gettextutils.py

Change-Id: Iaae19fc5018d83103e5f15ff76d6da686bfdf5f8
v3 credential set always needs --user option

Change-Id: Ieca76bb6ee2f328f4e33010623c25eb9c18e6952
Closes-Bug: #1372744
Remove unused reference to keyring

There's a unnecessary reference that is not being used.

Change-Id: I5ac85d2331385e4a31970b63fd17e650f82046ca