SQL Error while deleting sitemap.xml

Hi, guys,
Thanx a lot for your great module. You saved so much time for our project.

Have a small issue when trying to delete sitemap.xml (clicking Delete in the list of files). SQL Error in xmlsitemap.module in line 441. Generated SQL looks like DELETE FROM {xmlsitemap_sitemap} WHERE smid IN (0). But smid has type varchar (or character varying in Postgres in our case).

Seems it is very easy to fix that. Just change db_placeholders($smids) to db_placeholders($smids, 'varchar'). According to documentation db_placeholders function has default value 'int' for second parameter what is inapplicable in this case.