gnucash-htdocs master: Fix Github download links for 2.6.21.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash-htdocs/commit/05e679e6 (commit)
	from  https://github.com/Gnucash/gnucash-htdocs/commit/e1e1fdbc (commit)



commit 05e679e65d4d2b8db0b57e9bb0e426f065b1ff31
Author: John Ralls <jralls at ceridwen.us>
Date:   Sun Jun 3 16:21:27 2018 -0700

    Fix Github download links for 2.6.21.



Summary of changes:
 news/180410-2.6.21.news | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)