queue_log: Post QUEUESTART entry when Asterisk fully boots.

The QUEUESTART log entry has historically acted like a fully booted event
for the queue_log file.  When the QUEUESTART entry was posted to the log
was broken by the change made by ASTERISK-15863.

* Made post the QUEUESTART queue_log entry when Asterisk fully boots.
This restores the intent of that log entry and happens after realtime has
had a chance to load.

AST-1444 #close
Reported by: Denis Martinez

Review: https://reviewboard.asterisk.org/r/4282/
........

Merged revisions 430009 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/certified/branches/11.6@430029 65c4cc65-6c06-0410-ace0-fbb531ad65f3