Bug#872169: A solution to the issue

Thanks Innocent for the patch.
I've reviewed and tested it and it looks good.

The DSA team has installed opensp in www-master.debian.org (thanks!) and I've
uploaded the validation-onsgmls script, and created the corresponding calls in
the cron script so now both validate and validate-onsgmls are called and produce
logs.
Then we can compare tomorrow after the lessoften build.
If everything goes well, in 1-2 days we'll supersede the current "validate" with
the patch.

Best regards