Update language string

apps/contacts/templates/part.no_contacts.php

 <div id="firstrun">
-	<?php echo $l->t('You have no contacts in your list.') ?>
+	<?php echo $l->t('You have no contacts in your addressbook.') ?>
 	<div id="selections">
 		<input type="button" value="<?php echo $l->t('Import contacts') ?>" onclick="Contacts.UI.Addressbooks.doImport()" />
 		<input type="button" value="<?php echo $l->t('Add contact') ?>" onclick="Contacts.UI.Card.editNew()" />