[tracker] libtracker-data: check pointer before unref

[Ivan Frade <ifrade src gnome org>]

commit 34ceeff27313010f7bf405e85e826f4f6f242d82
Author: Ivan Frade <ivan frade nokia com>
Date:   Thu Sep 30 10:51:37 2010 +0300

    libtracker-data: check pointer before unref
    
    In some situations (file that is not a database) setting the journaling
    pragma returns NULL.

 src/libtracker-data/tracker-db-manager.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/src/libtracker-data/tracker-db-manager.c b/src/libtracker-data/tracker-db-manager.c
index 00a0a1c..495a6b7 100644
--- a/src/libtracker-data/tracker-db-manager.c
+++ b/src/libtracker-data/tracker-db-manager.c
@@ -218,7 +218,9 @@ db_set_params (TrackerDBInterface *iface,
 	tracker_db_interface_execute_query (iface, NULL, "PRAGMA auto_vacuum = 0;");
 
 	result_set = tracker_db_interface_execute_query (iface, NULL, "PRAGMA journal_mode = WAL;");
-	g_object_unref (result_set);
+        if (result_set) {
+                g_object_unref (result_set);
+        }
 
 	if (page_size != TRACKER_DB_PAGE_SIZE_DONT_SET) {
 		g_message ("  Setting page size to %d", page_size);