fixing php 5.3 compatibility

PHP Fatal error: Can't inherit abstract function OCP\ISession::set() (previously declared abstract in OC\Session\Session)

lib/private/session/session.php

@@ -8,7 +8,10 @@
 
 namespace OC\Session;
 
-abstract class Session implements \ArrayAccess, \OCP\ISession {
+use OCP\ISession;
+
+abstract class Session implements \ArrayAccess, ISession {
+
 	/**
 	 * $name serves as a namespace for the session keys
 	 *
@@ -16,36 +19,6 @@ abstract class Session implements \ArrayAccess, \OCP\ISession {
 	 */
 	abstract public function __construct($name);
 
-	/**
-	 * @param string $key
-	 * @param mixed $value
-	 */
-	abstract public function set($key, $value);
-
-	/**
-	 * @param string $key
-	 * @return mixed should return null if $key does not exist
-	 */
-	abstract public function get($key);
-
-	/**
-	 * @param string $key
-	 * @return bool
-	 */
-	abstract public function exists($key);
-
-	/**
-	 * should not throw any errors if $key does not exist
-	 *
-	 * @param string $key
-	 */
-	abstract public function remove($key);
-
-	/**
-	 * removes all entries within the cache namespace
-	 */
-	abstract public function clear();
-
 	/**
 	 * @param mixed $offset
 	 * @return bool