Revert of Flock master startup.

masters/start_master.sh

-#!/bin/sh
-# Copyright (c) 2016 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-# Starts a master and waits for its pidfile to become live. This was split out
-# of the Makefile in order to make a flock-able unit.
-
-set -e
-
-if [ -f twistd.pid ]; then
-  PID=`cat twistd.pid`
-  if [ -n $(ps -p$PID -o pid=) ]; then
-    echo "twistd.pid has pid $PID which is still alive. aborting."
-    exit 2
-  fi
-fi
-
-
-echo 'Now running Buildbot master.'
-python $SCRIPTS_DIR/common/twistd --no_save -y buildbot.tac
-
-echo 'Waiting for creation of twistd.pid...'
-while `test ! -f twistd.pid`; do sleep 1; done;
-
-PID=`cat twistd.pid`
-echo "twistd.pid contains new buildbot pid $PID"