Fixed forceExpiry() usage

Author: chillu

security/Member.php

@@ -423,7 +423,7 @@ public function logOut() {
 
 		$this->RememberLoginToken = null;
 		Cookie::set('alc_enc', null); // // Clear the Remember Me cookie
-		Cookie::forceExpiry('alc_enc');
+		Cookie::force_expiry('alc_enc');
 
 		// Switch back to live in order to avoid infinite loops when 
 		// redirecting to the login screen (if this login screen is versioned)