Free up s->d1->buffered_app_data.q properly.

PR#3286

(Imported from upstream's d52eb82781)

ssl/d1_lib.c

@@ -205,9 +205,12 @@ static void dtls1_clear_queues(SSL *s)
 
 	while ( (item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL)
 		{
-		frag = (hm_fragment *)item->data;
-		OPENSSL_free(frag->fragment);
-		OPENSSL_free(frag);
+		rdata = (DTLS1_RECORD_DATA *) item->data;
+		if (rdata->rbuf.buf)
+			{
+			OPENSSL_free(rdata->rbuf.buf);
+			}
+		OPENSSL_free(item->data);
 		pitem_free(item);
 		}
 	}