[Xymon] Patch: Regenerating HTML man pages

Hi,

while building the Debian package of xymon I noticed two issues with re-generating the HTML man pages:

a) Generating the man pages places the current day in the header, so the files cannot be generated reproducible (see https://en.wikipedia.org/wiki/Reproducible_builds). Using SOURCE_DATE_EPOCH (if it is set) solves this problem.

b) Without "-H localhost" as parameter of man2html the generated HTML files differ from what is packaged in the tarball. So I added this option.

The attached patch implements these two cases.

Greetings Roland