* Check minimal API and docker-py versions for all docker_* tests.
* Improve docker_swarm creation/destruction for tests.
* Fail when conditions aren't met.
* Don't hardcode address for advertise_addr.
These tests are doing string matches on the error condition. Update
them to match the new strings. This is probably okay to push out to old
releases even though it's technically backwards incompatible because
production playbooks won't be checking that a parameter was missing.
Param missing is something detected and fixed while writing the playbook.
