Add boot-services milestone marker for boot; fixed udev-addon init time.

failsafe.conf

 # Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 description     "Job to guarantee certain jobs start"
 author          "chromium-os-dev@chromium.org"
 
 # This job is used as a failsafe to guarantee certain jobs start
 # even if we fail to get a login screen.
 #
 # To improve boot performance, a variety of important jobs are
 # deliberately delayed until after the Chrome login screen is
 # presented.  By design, the services aren't needed right away, but
 # in test and debug environments, if Chrome fails to come up,
 # important facilities needed to debug the failure (such as
 # alternate VT consoles and ssh access) could fail to start.  This
 # job provides the event that those critical jobs should depend on
 # for starting.
 #
 # Standard usage:
 #   start on starting failsafe
 #   stop on stopping failsafe
 # Jobs that normally terminate in a bounded time (i.e. don't use
 # 'respawn') should omit the 'stop on' stanza.
 #
 # Note that this job can start on either of two events, both of
 # which are expected to occur in a normal boot.  To avoid firing
 # twice, this job starts once and doesn't terminate until system
 # shutdown.
+#
+# Also note that since system-services and the failsafe-delay
+# wait until boot-services have been started, jobs that start on
+# failsafe can assume that boot-services are started.
 
 start on starting system-services or stopped failsafe-delay
 stop on starting halt or starting reboot
 
 # Main process deliberately omitted