Merge pull request #1526 from thaJeztah/18.09_backport_completion_fix_service__force

[18.09 backport] Fix bash completion for `service update --force`

contrib/completion/bash/docker

@@ -3395,7 +3395,6 @@ _docker_service_update_and_create() {
 	local options_with_args="
 		--endpoint-mode
 		--entrypoint
-		--force
 		--health-cmd
 		--health-interval
 		--health-retries
@@ -3520,6 +3519,10 @@ _docker_service_update_and_create() {
 			--secret-rm
 		"
 
+		boolean_options="$boolean_options
+			--force
+		"
+
 		case "$prev" in
 			--env-rm)
 				COMPREPLY=( $( compgen -e -- "$cur" ) )