set default value for ip and ports in procfile.

rails and websocket servers will bind to 127.0.0.1 in deb & rpm packages now.

Procfile

@@ -1,3 +1,3 @@
-web: bundle exec rails s -p 3000
+web: bundle exec puma -b tcp://${ZAMMAD_BIND:=127.0.0.1}:${ZAMMAD_RAILS_PORT:=3000}
 worker: bundle exec script/scheduler.rb start -t
-websocket: bundle exec script/websocket-server.rb start
+websocket: bundle exec script/websocket-server.rb -b ${ZAMMAD_BIND:=127.0.0.1} -p ${ZAMMAD_WEBSOCKET_PORT:=6042} start