dockertest: fix subtests tag and dockerhelp

Signed-off-by: Jiří Župka <jzupka@redhat.com>
dockertest: Fixes problem with writing to parent config in subsub_enabled

Signed-off-by: Jiří Župka jzupka@redhat.com
subtests: Fixes import_export with env and run_cidfile.

Signed-off-by: Jiří Župka <jzupka@redhat.com>