[grilo-plugins] tracker: fix warning due to unref NULL

[Juan A. Suarez Romero <jasuarez src gnome org>]

commit 545a3512a8287ea2999fee6127d50c6c42201be5
Author: Lionel Landwerlin <lionel g landwerlin linux intel com>
Date:   Wed Jan 19 11:47:32 2011 +0000

    tracker: fix warning due to unref NULL
    
    Signed-off-by: Lionel Landwerlin <lionel g landwerlin linux intel com>
    Signed-off-by: Juan A. Suarez Romero <jasuarez igalia com>

 src/tracker/grl-tracker.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/tracker/grl-tracker.c b/src/tracker/grl-tracker.c
index 8b6e8f4..73317d3 100644
--- a/src/tracker/grl-tracker.c
+++ b/src/tracker/grl-tracker.c
@@ -285,7 +285,8 @@ grl_tracker_source_set_property (GObject      *object,
 
   switch (propid) {
   case PROP_TRACKER_CONNECTION:
-    g_object_unref (G_OBJECT (priv->tracker_connection));
+    if (priv->tracker_connection != NULL)
+      g_object_unref (G_OBJECT (priv->tracker_connection));
     priv->tracker_connection = g_object_ref (g_value_get_object (value));
     break;