gnucash-htdocs master: Fix some errors found by w3c validator

[Frank H.Ellenberger]

Updated	 via  https://github.com/Gnucash/gnucash-htdocs/commit/295063d4 (commit)
	from  https://github.com/Gnucash/gnucash-htdocs/commit/bc32bdc2 (commit)



commit 295063d46c95afa5dad1f0c5447250765fa97e3e
Author: fell <frank.h.ellenberger at gmail.com>
Date:   Sun Apr 8 06:44:36 2018 +0200

    Fix some errors found by w3c validator



Summary of changes:
 externals/gnucash.css  | 2 +-
 externals/header.phtml | 2 +-
 index.phtml            | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)