Fix upgrade

scripts/upgrade

@@ -25,7 +25,7 @@ db_pwd=$(ynh_app_setting_get --app=$app --key=mysqlpwd)
 language=$(ynh_app_setting_get --app=$app --key=language)
 
 trustedversion="4.4-1+stretch"
-if ynh_permission_has_user --permission=main --user=visitors
+if [ ynh_permission_has_user --permission=main --user=visitors ]
 then
 	is_public=0
 else