empathy_call_window_content_added_cb: fix pad leak
empathy_call_window_content_added_cb: fix pad leak

https://bugzilla.gnome.org/show_bug.cgi?id=670745

GNOME/telepathy-account-widgets,Distrotech/telepathy-account-widgets,Distrotech/telepathy-account-widgets,GNOME/telepathy-account-widgets,GNOME/telepathy-account-widgets