[tracker] libtracker-data: Fix unsetting tracker:secondaryIndex

[Philip Van Hoof <pvanhoof src gnome org>]

commit 03998483a65eaba5ad16312a4703a36d5acb89dc
Author: Philip Van Hoof <philip codeminded be>
Date:   Wed Oct 20 16:13:41 2010 +0200

    libtracker-data: Fix unsetting tracker:secondaryIndex

 src/libtracker-data/tracker-data-manager.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/libtracker-data/tracker-data-manager.c b/src/libtracker-data/tracker-data-manager.c
index 8d3ccf2..cb92a45 100644
--- a/src/libtracker-data/tracker-data-manager.c
+++ b/src/libtracker-data/tracker-data-manager.c
@@ -426,7 +426,7 @@ update_property_value (const gchar      *ontology_path,
 	}
 
 
-	if (!error && needed) {
+	if (!error && needed && object) {
 		tracker_data_insert_statement (NULL, subject,
 		                               predicate, object,
 		                               &error);