[#2582] dbus_codec_list: initialize array variable to NULL

... in case the dbus call will fail. Else it will cause a segfault.

sflphone-client-gnome/src/dbus/dbus.c

@@ -1195,7 +1195,7 @@ dbus_codec_list()
 {
 
     GError *error = NULL;
-    gchar** array;
+    gchar** array = NULL;
     org_sflphone_SFLphone_ConfigurationManager_get_codec_list (
             configurationManagerProxy,
             &array,