silence error for "invalid enum handover_scope value: none"

If no target cell got selected in a handover attempt, enum value NO_HANDOVER is
used. In that case, do not log a lot of errors saying
"invalid enum handover_scope value: none" -- they are misleading.

Change-Id: I98e748bea58ebb02812b6aaa6431c7d4b813242d
diff --git a/src/osmo-bsc/handover_fsm.c b/src/osmo-bsc/handover_fsm.c
index 7406a97..6d0c2d4 100644
--- a/src/osmo-bsc/handover_fsm.c
+++ b/src/osmo-bsc/handover_fsm.c
@@ -694,6 +694,7 @@
 		LOGP(DHO, LOGL_ERROR, "invalid enum handover_scope value: %s\n",
 		     handover_scope_name(scope));
 		/* use "normal" HO_INTRA_BSC counter... */
+	case HO_NO_HANDOVER:
 	case HO_INTRA_BSC:
 		return result_counter_HANDOVER(result);
 	case HO_INTER_BSC_OUT: