Adding an extra index to speed-up data synchronization for large volumes of data.

SVN:trunk[4128]

synchro/synchrodatasource.class.inc.php

@@ -1508,6 +1508,7 @@ class SynchroReplica extends DBObject implements iDisplay
 			"db_key_field" => "id",
 			"db_finalclass_field" => "",
 			"display_template" => "",
+			"indexes" => array( array ('dest_class', 'dest_id'), ),
 		);
 		MetaModel::Init_Params($aParams);
 		MetaModel::Init_InheritAttributes();