use null instead of -1 on all getUser()

lib/public/user.php

@@ -51,7 +51,7 @@ class User {
 	 *
 	 * Get a list of all users.
 	 */
-	public static function getUsers($search = '', $limit = -1, $offset = 0) {
+	public static function getUsers($search = '', $limit = null, $offset = null) {
 		return \OC_USER::getUsers();
 	}
 

lib/user/backend.php

@@ -99,7 +99,7 @@ abstract class OC_User_Backend implements OC_User_Interface {
 	*
 	* Get a list of all users.
 	*/
-	public function getUsers($search = '', $limit = -1, $offset = 0) {
+	public function getUsers($search = '', $limit = null, $offset = null) {
 		return array();
 	}
 

lib/user/dummy.php

@@ -100,7 +100,7 @@ class OC_User_Dummy extends OC_User_Backend {
 		*
 		* Get a list of all users.
 		*/
-	public function getUsers($search = '', $limit = -1, $offset = 0) {
+	public function getUsers($search = '', $limit = null, $offset = null) {
 		return array_keys($this->users);
 	}
 

lib/user/interface.php

@@ -48,7 +48,7 @@ interface OC_User_Interface {
 	*
 	* Get a list of all users.
 	*/
-	public function getUsers($search = '', $limit = -1, $offset = 0);
+	public function getUsers($search = '', $limit = null, $offset = null);
 
 	/**
 	* @brief check if a user exists