Fixing alerts on router restart.

Splitting the process type connectivity matrix to 'keep ports' and 'send
ports'; the 'keep ports' matrix is used to clean up unnecessary ports after
forking a new process, and the 'send ports' matrix determines which process
types expect to get created process ports.

Unfortunately, the original single connectivity matrix no longer works because
of an application stop delay caused by prototypes.  Existing applications
should not get the new router port at the moment.

src/nxt_port.c

@@ -217,7 +217,7 @@ nxt_port_send_new_port(nxt_task_t *task, nxt_runtime_t *rt,
 
         port = nxt_process_port_first(process);
 
-        if (nxt_proc_conn_matrix[port->type][new_port->type]) {
+        if (nxt_proc_send_matrix[port->type][new_port->type]) {
             (void) nxt_port_send_port(task, port, new_port, stream);
         }