subtests...start: Fix not ignoring error message

*  rerun_long_term_app did not properly specify
   to skip the error-message check - since an error
   message is expected.

*  Base class postprocess() was not generalized enough
   in the OutputGood check for all tests.

Signed-off-by: Chris Evich <cevich@redhat.com>
subtests...save_load: Fix initialize() & DockerCmd() calls

Signed-off-by: Chris Evich <cevich@redhat.com>
subtests...attach: Fix missing config option

Signed-off-by: Chris Evich <cevich@redhat.com>
subtests...images: Update info log call.

Signed-off-by: Chris Evich <cevich@redhat.com>
subtests...kill/bad: Fix use valid signal name

Signed-off-by: Chris Evich <cevich@redhat.com>
dockertest.images: Add FIXME comment

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