Fixes for su on freebsd

Addresses multiple issues when using su on freebsd including
* su prompt differs between platforms, so turned that check into a
  regex comparison instead of a simple string comparison
* not using '-c' after su causes problems, so added that for all
  platforms
* fixed quoting issues due to multiple uses of '-c' introduced by
  the above fix

Fixes #7503
Fixes #7507
open_iscsi module: support RC 21 when listing logged-in target
Merge pull request #7539 from jimi-c/issue_7503_freebsd_su_fixes

Fixes for su on freebsd
Update test strategies guide.
Recent BSD su work introduced a failing test. Removed leading space from the assertion that seems to be the culprit.
Merge pull request #7563 from tima/fix-testutils-su

Recent BSD su work introduced a failing test. Removed leading space from...
Correct issue of handlers running on all hosts incorrectly

Also adds an integration test to catch this bug in the future.

Fixes #7559
Update test_strategies.rst

Typo - State should have been stage.
Update test_strategies.rst

Changed unit tests to unit test for the singular playbook...
Merge pull request #7532 from oasiswork/devel

open_iscsi module: support RC 21 when listing logged-in target
Merge pull request #7568 from MorrisA/patch-1

Update test_strategies.rst