when reverting import batch: don't try to delete items that are already deleted

Signed-off-by: Chris Cormack <crc@liblime.com>
Signed-off-by: Joshua Ferraro <jmf@liblime.com>

C4/ImportBatch.pm

@@ -596,6 +596,7 @@ sub BatchRevertItems {
 
     my $sth = $dbh->prepare_cached("SELECT import_items_id, itemnumber
                                    FROM import_items
+                                   JOIN items USING (itemnumber)
                                    WHERE import_record_id = ?");
     $sth->bind_param(1, $import_record_id);
     $sth->execute();