[couchdb-glib] Avoid warning when unref'ing a NULL object

[Rodrigo Moya <rodrigo src gnome org>]

commit cba0474f27bb4d78f07a1f21dc75f08745a34c1b
Author: Sam Thursfield <ssssam gmail com>
Date:   Mon May 31 18:51:35 2010 +0200

    Avoid warning when unref'ing a NULL object

 couchdb-glib/couchdb-database.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/couchdb-glib/couchdb-database.c b/couchdb-glib/couchdb-database.c
index 8929508..e228a7e 100644
--- a/couchdb-glib/couchdb-database.c
+++ b/couchdb-glib/couchdb-database.c
@@ -87,7 +87,8 @@ couchdb_database_set_property (GObject *object,
 
 	switch (prop_id) {
 	case PROP_SESSION:
-		g_object_unref (G_OBJECT (database->priv->session));
+		if (database->priv->session != NULL)
+			g_object_unref (G_OBJECT (database->priv->session));
 		database->priv->session = g_object_ref (G_OBJECT (g_value_get_object (value)));
 		break;
 	case PROP_DATABASE_NAME: