Change completion for services to use names by default, and bring back
support for the `DOCKER_COMPLETION_SHOW_SERVICE_IDS` env-var
https://github.com/docker/cli/blob/f9ced58158d5e0b358052432244b483774a1983d/contrib/completion/bash/docker#L41-L43
Before this patch:
docker service ps
c9vrp2pwni9gx5ghat20rjpcy hmthf0tqws9xpmd87ok7diqly
With this patch:
docker service ps<TAB>
databaseservice webservice
export DOCKER_COMPLETION_SHOW_SERVICE_IDS=yes
docker service ps<TAB>
c9vrp2pwni9gx5ghat20rjpcy databaseservice hmthf0tqws9xpmd87ok7diqly webservice
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>