sf_node_nodeapi needs check for case 'insert'

In sf_node.module, sf_node_nodeapi needs to check $options on case $op equals 'insert'. So

        $options = salesforce_api_fieldmap_options('node_'. $node->type, NULL, TRUE);

should be

        $options = salesforce_api_fieldmap_options('node_'. $node->type, NULL, TRUE);

        if ( empty($$options) ) {
        	return;
        }

Otherwise code attempts to export content type even with out a valid map.