[Orgmode] Tiny bug in org-html

[Tom Breton (Tehom)]

In the course of working with org-html, I noticed that
`org-export-as-html-and-open' seems to have a bug.  `kill-buffer'
needs an argument, a buffer, presumably the buffer that
`org-open-file' makes.  This code is "protected" by the nil default
value of `org-export-kill-product-buffer-when-displayed', so the bug
may not have been obvious.

        Tom Breton (Tehom)