Added missing placeholder "Mailbox quota" in mail module.

tbrehm

2012-12-19 789ca03af109f35403f8ea965268fdce4f882ce5

 interface/web/mail/lib/lang/en.lng

@@ -47,5 +47,5 @@
$wb['Global Filters'] = 'Global Filters';
$wb['Domain Alias'] = 'Domain Alias';
$wb["Relay Recipients"] = 'Relay Recipients';

$wb['Mailbox quota'] = 'Mailbox quota';
?>