[empathy] Make sure to not ref a NULL object

[Xavier Claessens <xclaesse src gnome org>]

commit b19d8cde60b98f0f86a49a8eed0885222e808f2f
Author: Xavier Claessens <xclaesse gmail com>
Date:   Tue Feb 17 16:11:48 2009 +0100

    Make sure to not ref a NULL object
---
 libempathy/empathy-contact.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/libempathy/empathy-contact.c b/libempathy/empathy-contact.c
index 09da70f..d248b2d 100644
--- a/libempathy/empathy-contact.c
+++ b/libempathy/empathy-contact.c
@@ -274,6 +274,9 @@ set_tp_contact (EmpathyContact *contact,
 {
   EmpathyContactPriv *priv = GET_PRIV (contact);
 
+  if (tp_contact == NULL)
+    return;
+
   g_assert (priv->tp_contact == NULL);
   priv->tp_contact = g_object_ref (tp_contact);
   priv->presence = empathy_contact_get_presence (contact);