more style/function tweaks

plugins/docker-options/subcommands/add

@@ -10,7 +10,7 @@ docker_options_add_cmd() {
   verify_app_name "$2" && local APP="$2"
   read -ra passed_phases <<< "$(get_phases "$3")"
   shift 3 # everything else passed is the docker option
-  passed_docker_option="$*"
+  local passed_docker_option="$*"
   [[ -z "$passed_docker_option" ]] && dokku_log_fail "Please specify docker options to add to the phase"
   add_passed_docker_option passed_phases[@] "${passed_docker_option[@]}"
 }