handover: don't create negative lchan use counts

trans_lchan_change() takes care of use counts for us.
diff --git a/openbsc/src/handover_logic.c b/openbsc/src/handover_logic.c
index f3f5d6c..2c75497 100644
--- a/openbsc/src/handover_logic.c
+++ b/openbsc/src/handover_logic.c
@@ -215,9 +215,6 @@
 	/* do something to re-route the actual speech frames ! */
 	//tch_remap(ho->old_lchan, ho->new_lchan);
 
-	/* release old lchan */
-	put_lchan(ho->old_lchan);
-
 	talloc_free(ho);
 
 	return 0;