chan_sip: Give more time for TCP/TLS threads to stop.

The unload process currently tells each TCP/TLS to terminate but
does not wait for them to do so. This introduces a race condition
where the container holding the threads may be destroyed before
the threads are able to remove themselves from it. When they
finally do the container is invalid and can't be used causing a
crash.

A previous change existed which waited a bit to wait for any
stranglers to finish. This change extends this and waits longer.

ASTERISK-25961 #close

Change-Id: Idc6262b670ca49ede32061159e323b7b63c6f3c6

channels/chan_sip.c

@@ -35298,7 +35298,7 @@ static int unload_module(void)
 	struct sip_pvt *p;
 	struct sip_threadinfo *th;
 	struct ao2_iterator i;
-	int wait_count;
+	struct timeval start;
 
 	ast_sip_api_provider_unregister();
 
@@ -35450,11 +35450,11 @@ static int unload_module(void)
 	 * joinable.  They can die on their own and remove themselves
 	 * from the container thus resulting in a huge memory leak.
 	 */
-	wait_count = 1000;
-	while (ao2_container_count(threadt) && --wait_count) {
+	start = ast_tvnow();
+	while (ao2_container_count(threadt) && (ast_tvdiff_sec(ast_tvnow(), start) < 5)) {
 		sched_yield();
 	}
-	if (!wait_count) {
+	if (ao2_container_count(threadt)) {
 		ast_debug(2, "TCP/TLS thread container did not become empty :(\n");
 	}