minor tweaks in pgm code

src/pgm_sender.cpp

@@ -130,8 +130,12 @@ void zmq::pgm_sender_t::revive ()
 
 zmq::pgm_sender_t::~pgm_sender_t ()
 {
+    zmq_log (4, "pgm_sender_t destructor, %s(%i)\n",
+        __FILE__, __LINE__);
+
     if (out_buffer) {
         pgm_socket.free_buffer (out_buffer);
+        out_buffer = NULL;
     }
 }
 

src/pgm_socket.cpp

@@ -358,7 +358,7 @@ int zmq::pgm_socket_t::open_transport (void)
     //  Sender transport.
     } else {
 
-        //  Set transport->can_recv = FALSE, waiting_pipe wont not be read.
+        //  Set transport->can_recv = FALSE, waiting_pipe will not be read.
         rc = pgm_transport_set_send_only (g_transport, TRUE);
         if (rc != pgm_ok) {
             errno = EINVAL;