dockertest: run fix import and force repo busybox in run_remote_tag.

* fix syntax in attach to avoid skipping of super class function.

Signed-off-by: Jiří Župka <jzupka@redhat.com>
subtests/docker_cli/attach: Pylint fixups

*  Add methods for matching expected
   or unexpected configuration strings
   against docker command output.

*  Add method to assemble list of
   sub-subtest specific parameters
   to output-matching methods.

*  Make postprocess method generic,
   by taking result of assembling
   parameter lists, and passing them
   to matching methods.

*  Make sig_proxy sub-subtests postprocess
   generic by using new specialized
   check_containers() method.

Signed-off-by: Chris Evich <cevich@redhat.com>
subtests...psa: Improved test reliability

*  Fixed: Test incorrectly called get_container_list()
   instead of list_containers()

*  Fixed:  Test would break if image needed to be downloade.

*  Fixed: Test did not use common name generation.

*  Fixed: Inaccurate list-size comparison condition.  Check
   existance of container id instead.

Signed-off-by: Chris Evich <cevich@redhat.com>