Comment 3 for bug 1587941

Reviewed: https://review.openstack.org/325189
Committed: https://git.openstack.org/cgit/openstack/rally/commit/?id=567b9d975b6a2e97ed67da59d78e4f1b25687e7d
Submitter: Jenkins
Branch: master

commit 567b9d975b6a2e97ed67da59d78e4f1b25687e7d
Author: Alexander Maretskiy <email address hidden>
Date: Fri Jun 3 11:56:59 2016 +0300

    [Plugins] Fix vm.utils._run_command_over_ssh

    Method vm.utils._run_command_over_ssh has been reworked,
    also there are related changes in task.validation:
      * command parameters are processed in different way,
        so UnboundLocalError and another potential issues
        are resolved
      * removed redundant check `validation.check_command_dict',
        because scenarios which uses _run_command_over_ssh already
        check command with validator `validation.valid_command',
        so `check_command_dict' is run twice
      * as result, unit test `test__run_command_over_ssh_fails'
        is removed since it checks invocation of
        `check_command_dict' by `_run_command_over_ssh'
      * os.path.expanduser is moved from check_command_dict
        to _run_command_over_ssh since validation should not modify
        data, especially when it is being done implicitly
      * unit test `validation.check_command_dict' is extended
        and rewritten with DDT

    Change-Id: Ib14012bf6e91fd6f7b4dd32766daa191c320e314
    Closes-Bug: 1587941