Fix substitution of comma to space character, suggested by @albers

Signed-off-by: Morten Hekkvang <morten.hekkvang@sbab.se>
(cherry picked from commit b85e1e2efe)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

contrib/completion/bash/docker

@@ -551,7 +551,7 @@ __docker_complete_nodes() {
 # precedence over the environment setting.
 __docker_services() {
 	local format='{{.Name}}'  # default: service name only
-	[ "${DOCKER_COMPLETION_SHOW_SERVICE_IDS}" = yes ] && format='{{.ID}},{{.Name}}' # ID & name
+	[ "${DOCKER_COMPLETION_SHOW_SERVICE_IDS}" = yes ] && format='{{.ID}} {{.Name}}' # ID & name
 
 	if [ "$1" = "--id" ] ; then
 		format='{{.ID}}' # IDs only