bash completion for docker swarm join-token

Signed-off-by: Harald Albers <github@albersweb.de>
(cherry picked from commit 42b4d6ebe4)
Signed-off-by: Tibor Vass <tibor@docker.com>

contrib/completion/bash/docker

@@ -1815,6 +1815,7 @@ _docker_swarm() {
 		init
 		inspect
 		join
+		join-token
 		leave
 		update
 	"
@@ -1884,6 +1885,20 @@ _docker_swarm_join() {
 	esac
 }
 
+_docker_swarm_join-token() {
+	case "$cur" in
+		-*)
+			COMPREPLY=( $( compgen -W "--help --quiet -q --rotate" -- "$cur" ) )
+			;;
+		*)
+			local counter=$( __docker_pos_first_nonflag )
+			if [ $cword -eq $counter ]; then
+				COMPREPLY=( $( compgen -W "manager worker" -- "$cur" ) )
+			fi
+			;;
+	esac
+}
+
 _docker_swarm_leave() {
 	case "$cur" in
 		-*)