Destroying temporary router configuration.

The lifespan of a listening socket is longer than both router
configuration's and temporary router configuration's lifespan,
so the sockets should be stored in persistent queues. Safety
is ensured by the fact that the router processes only one new
configuration at any time.

src/nxt_router.h

@@ -66,12 +66,6 @@ typedef struct {
 
 
 typedef struct {
-    nxt_queue_t            creating;   /* of nxt_socket_conf_t */
-    nxt_queue_t            pending;    /* of nxt_socket_conf_t */
-    nxt_queue_t            updating;   /* of nxt_socket_conf_t */
-    nxt_queue_t            keeping;    /* of nxt_socket_conf_t */
-    nxt_queue_t            deleting;   /* of nxt_socket_conf_t */
-
 #if (NXT_TLS)
     nxt_queue_t            tls;        /* of nxt_router_tlssock_t */
 #endif