Fix inability to shutdown gracefully due to an unending channel reference.

message.c makes use of a special message queue channel that exists
in thread storage. This channel never goes away due to the fact that
the taskprocessor used by message.c does not get shut down, meaning
that it never ends the thread that stores the channel.

This patch fixes the problem by shutting down the taskprocessor when
Asterisk is shut down. In addition, the thread storage has a destructor
that will release the channel reference when the taskprocessor is destroyed.

(closes issue AST-937)
Reported by Jason Parker
Patches:
	AST-937.patch uploaded by Mark Michelson (License #5049)
Tested by Jason Parker
........

Merged revisions 372885 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@372888 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/_private.h

@@ -48,6 +48,7 @@ int ast_cel_engine_reload(void);	/*!< Provided by cel.c */
 int ast_ssl_init(void);                 /*!< Provided by ssl.c */
 int ast_test_init(void);            /*!< Provided by test.c */
 int ast_msg_init(void);             /*!< Provided by message.c */
+void ast_msg_shutdown(void);        /*!< Provided by message.c */
 
 /*!
  * \brief Reload asterisk modules.

main/asterisk.c

@@ -1702,6 +1702,7 @@ static int can_safely_quit(shutdown_nice_t niceness, int restart)
 	 * (if in batch mode). really_quit happens to call it again when running
 	 * the atexit handlers, otherwise this would be a bit early. */
 	ast_cdr_engine_term();
+	ast_msg_shutdown();
 
 	if (niceness == SHUTDOWN_NORMAL) {
 		time_t s, e;

main/message.c

@@ -756,7 +756,18 @@ static void chan_cleanup(struct ast_channel *chan)
 	ast_channel_unlock(chan);
 }
 
-AST_THREADSTORAGE(msg_q_chan);
+static void destroy_msg_q_chan(void *data)
+{
+	struct ast_channel **chan = data;
+
+	if (!*chan) {
+		return;
+	}
+
+	ast_channel_release(*chan);
+}
+
+AST_THREADSTORAGE_CUSTOM(msg_q_chan, NULL, destroy_msg_q_chan);
 
 /*!
  * \internal
@@ -1318,3 +1329,8 @@ int ast_msg_init(void)
 
 	return res;
 }
+
+void ast_msg_shutdown(void)
+{
+	msg_q_tp = ast_taskprocessor_unreference(msg_q_tp);
+}