Remove `session_id_regenerate` from here

Jenkins somewhat complains that there are already sent headers.

lib/private/user/session.php

@@ -157,7 +157,6 @@ class Session implements Emitter, \OCP\IUserSession {
 		if($user !== false) {
 			if (!is_null($user)) {
 				if ($user->isEnabled()) {
-					session_regenerate_id(true);
 					$this->setUser($user);
 					$this->setLoginName($uid);
 					$this->manager->emit('\OC\User', 'postLogin', array($user, $password));