Avoid using raw sql in SpecialUndelete.php

Avoid using raw sql in SpecialUndelete.php

The where part for the ar_timestamp was raw sql.
Refactored to avoid this. Now the IN-List is created by the database
abstraction layer. The addQuotes and implode with comma is done there.
Just the call to Database::timestamp is still needed.

This also avoids a '1 = 1' in sql.

Change-Id: I1deb055a1437ae84fc8a4e8cf2976e18c15bda39