Add "--rm" to each "docker run" command, so they don't continuously fill up disk space.
Fix this even in the pipework script. We don't use the code path there, but by always having --rm after "docker run" (same line or next line), a new lint script in osmo-ci I8ab9c291504475d670bdefc50c4524c5bdd4c880 can help us avoid this in the future.
In ttcn3-ggsn-test/jenkins.sh, move one existing --rm in a later line upwards so the linter can find it.
