Compatibility to apachesolr 2.x-dev

In order to index translations, the following change is need to index translation in apachesolr.module

            //if ($translation_document = apachesolr_node_to_document($translation->nid, $namespace)) {
            if ($translation_document = apachesolr_node_to_document(node_load($translation->nid), $namespace)) {

If only the Node ID is passed, this produces a lot of errors because the $node object is expected by apachesolr_node_to_document();