Improve bash completion for `docker rm`

`docker rm` can delete containers in state=created, too.

Signed-off-by: Harald Albers <github@albersweb.de>

contrib/completion/bash/docker

@@ -101,6 +101,10 @@ __docker_complete_containers_all() {
 	__docker_complete_containers "$@" --all
 }
 
+__docker_complete_containers_removable() {
+	__docker_complete_containers "$@" --filter status=created --filter status=exited
+}
+
 __docker_complete_containers_running() {
 	__docker_complete_containers "$@" --filter status=running
 }
@@ -1430,7 +1434,7 @@ _docker_container_rm() {
 						;;
 				esac
 			done
-			__docker_complete_containers_stopped
+			__docker_complete_containers_removable
 			;;
 	esac
 }