Fixed SQL query in DNS slave datasource component.

Author: Till Brehm

interface/lib/classes/custom_datasource.inc.php

@@ -72,7 +72,7 @@ function slave_dns_servers($field, $record) {
 			$client = $app->db->queryOneRecord("SELECT default_slave_dnsserver FROM sys_group, client WHERE sys_group.client_id = client.client_id and sys_group.groupid = ?", $client_group_id);
 			$sql = "SELECT server_id,server_name FROM server WHERE server_id = ?";
 		} else {
-			$sql = "SELECT server_id,server_name FROM server WHERE dns_server = 1 ORDER BY server_name AND mirror_server_id = 0";
+			$sql = "SELECT server_id,server_name FROM server WHERE dns_server = 1 AND mirror_server_id = 0 ORDER BY server_name";
 		}
 		$records = $app->db->queryAllRecords($sql, $client['default_slave_dnsserver']);
 		$records_new = array();