Genericize the allocation and destruction of taskprocessor listeners.

The goal of this is to take the responsibility away from individual
listeners to be sure to properly unref the taskprocessor.



git-svn-id: https://origsvn.digium.com/svn/asterisk/team/mmichelson/threadpool@376121 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/astobj2.c

@@ -431,6 +431,7 @@ static int internal_ao2_ref(void *user_data, int delta, const char *file, int li
 	int ret;
 
 	if (obj == NULL) {
+		ast_backtrace();
 		ast_assert(0);
 		return -1;
 	}