Yoast/wordpress-seo — pull request #1093 by jrfnl (2014-05-08 05:00:40+00:00)
Title: Fix issue #1068 - error in sitemap_index.xml if post type does not ...

...contain any posts

Also fixes a typo in the same line - this may well be the cause of the incorrect sitemap last modified dates as reported in #930, #883, #1066, #525, #873