fix compiler warnings

src/set/gnunet-service-set.c

@@ -206,7 +206,6 @@ static void
 incoming_destroy (struct Operation *op)
 {
   struct Listener *listener;
-  struct GNUNET_CADET_Channel *channel;
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Destroying incoming operation %p\n",

src/set/gnunet-service-set_union.c

@@ -1368,26 +1368,6 @@ send_client_element (struct Operation *op,
 }
 
 
-/**
- * Destroy remote channel.
- *
- * @param op operation
- */
-static void
-destroy_channel (struct Operation *op)
-{
-  struct GNUNET_CADET_Channel *channel;
-
-  if (NULL != (channel = op->channel))
-  {
-    /* This will free op; called conditionally as this helper function
-       is also called from within the channel disconnect handler. */
-    op->channel = NULL;
-    GNUNET_CADET_channel_destroy (channel);
-  }
-}
-
-
 /**
  * Signal to the client that the operation has finished and
  * destroy the operation.