Bug#900749: Bug #900749: [www.debian.org] webwml build takes too long

Hello all

I'm providing here some info about the current situation.

The last build job was done with no updates in the git repo.
This time the webwml job took 1 hour approx:

3stattrans finished (at Tue Jun  5 07:27:30 UTC 2018)
run-parts: executing /srv/www.debian.org/cron/parts/4webwml
4webwml finished (at Tue Jun  5 08:29:51 UTC 2018)

The logs of this job can be found in:

https://www-master.debian.org/build-logs/webwml/often.no-changes-git.log
https://www-master.debian.org/build-logs/webwml/git_update.no-changes-git.log
https://www-master.debian.org/build-logs/webwml/stattrans.no-changes-git.log
https://www-master.debian.org/build-logs/webwml/wml_run.no-changes-git.log

So I think this is the "bare minimum" that we can aim without changes to the
makefiles or scripts.

Cheers