[PATCH] Fix colspan of commitfest topic headers

Hi www,

After my last pgweb contributions ended in a disaster, I have shied
away from hacking on the website. But it may be time to give it
another shot. :)

Here's a patch to fix the upper right corner of the table on
commitfest pages, for example:
https://commitfest.postgresql.org/action/commitfest_view?id=24

Previously, together with the separate last column, the topic headers
were 6 cols wide, compared to other rows with 5 cols, which made the
layout look odd.

Beware, I only tried change in the browser, without actually running
my own pgcommitfest system, so there's always a chance I could have
broken something.

Regards,
Marti