* Use a random query id for dns lookups

This can also fix a rare case of long-running bots
becoming zombies where they disconnect from the hub
and never reconnect, due to their query id rolling
over short max (65535) while the remote server
truncates the id, resulting in queries seemingly
never being returned.

src/adns.c

@@ -148,7 +148,6 @@ typedef struct {
 } dns_cache_t;
 
 
-static int query_id = 1;
 static dns_header_t _dns_header = {0, 0, 0, 0, 0, 0};
 static dns_query_t *query_head = NULL;
 static dns_host_t *hosts = NULL;
@@ -308,7 +307,7 @@ static dns_query_t *alloc_query(void *client_data, dns_callback_t callback, cons
 {
 	dns_query_t *q = (dns_query_t *) my_calloc(1, sizeof(*q));
 
-	q->id = query_id++;
+	q->id = randint(65534);
 	q->query = strdup(query);
 	q->answers = 0;
 	q->callback = callback;