[PATCH] doc: create manpage folders with right permissions

[David Bremner]

Antoine Amarilli <a3nm at a3nm.net> writes:

> Avoids the issue where umask can make man pages unreadable after
> installation. Relevant email on the mailing-list:
> <87h8rt30sy.fsf at fifthhorseman.net>

Pushed to master, thanks for your contribution.

d