security/openssh-portable: Remove groff dependency

[koobs]

Summary

security/openssh-portable: Remove groff dependency

An unconditional dependency on groff was added in ports r441907 [1] as part of
bug 213725 (groff removal from base). OpenSSH release-5.7 notes the following:

 * Use mandoc as preferred manpage formatter if it is present, followed
   by nroff and groff respectively.
   
This change removes groff as an unconditional dependency allowing mandoc to be
used.

It additionally explicitly sets 'mantype', which ensures that man pages
are installed in the same location (LOCALBASE/man) independently from the
generator used. Without this, a packaging (pkg-plist) error is observed
(installing man pages into LOCALBASE/doc not LOCALBASE/man), which was
presumably the genesis of the groff dependency addition in the first place.

[1] http://svnweb.freebsd.org/changeset/ports/441907

Reviewed_by: bdrewery (maintainer), allanjude
Approved by: bdrewery (maintainer)
Differential_Revision: D11793

Test Plan

• portlint: WARN (warning delta same pre/post these changes)
• testport: OK (poudriere: 12amd64, 11(1)amd64, 103i386)

[koobs]

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