Merged revisions 272370 via svnmerge from

Merged revisions 272370 via svnmerge from
https://origsvn.digium.com/svn/asterisk/trunk

........
  r272370 | russell | 2010-06-23 18:09:28 -0500 (Wed, 23 Jun 2010) | 23 lines

  Resolve some errors produced during module unload of chan_iax2.

  The external test suite stops Asterisk using the "core stop gracefully" command.
  The logs from the tests show that there are a number of problems with Asterisk
  trying to cleanly shut down.  This patch addresses the following type of error
  that comes from chan_iax2:

  [Jun 22 16:58:11] ERROR[29884]: lock.c:129 __ast_pthread_mutex_destroy:
                  chan_iax2.c line 11371 (iax2_process_thread_cleanup):
                  Error destroying mutex &thread->lock: Device or resource busy

  For an example in the context of a build, see:

  http://bamboo.asterisk.org/browse/AST-TRUNK-739/log

  The primary purpose of this patch is to change the thread pool shutdown
  procedure to be more explicit to ensure that the thread exits from a point
  where it is not holding a lock.  While testing that, I encountered various
  crashes due to the order of operations in unload_module() being problematic.
  I reordered some things there, as well.

  Review: https://reviewboard.asterisk.org/r/736/
........

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.2@272371 65c4cc65-6c06-0410-ace0-fbb531ad65f3