*/*: Rework manpages handling in Samba-related ports

[michaelo]

Summary

• Remove outdated, incorrect, precompiled manpages from ${FILESDIR}/files/man.
• Properly disable manpages generation since XSLTPROC was set to true(1) WAF always assumed xsltproc(1) to work and if any automatic dependency pulled in textproc/docbook-xsl, manpages were generated even if explicitly disabled.

Approved by: jrm (mentor), otis (mentor), ...

[jrm]

devel/tevent/Makefile

48–49

I'm confused by this comment. If there are no man pages for this port, why is there an OPTION and the associated logic?

devel/tevent016/Makefile

49–50

Same comment.

[michaelo]

devel/tevent/Makefile

48–49

The actual block has been there, I added the comment on purpose for the following reason:

• consistency with other Samba-related ports
• if a manpage is added only pkg-plist needs to be modified.

[jrm]

devel/tevent/Makefile

48–49

Let's remove it. If necessary, it's not that hard to copy a couple of lines from the other ports in the future. A MANPAGES option and the associated logic for ports that don't install any manpages is kinda weird.

[michaelo]

Address @jrm's comments