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"