Deorbit "Getting started on HP-UX systems"

We don't really support HP-UX anymore; no need to clutter up
the documentation with it.

Change-Id: Ib75f4f137c3cfcb5ab2aece3746964f1cfbab051
Reviewed-on: http://gerrit.openafs.org/11574
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: D Brashear <shadow@your-file-system.com>
Deorbit "Getting started on IRIX systems"

IRIX is mostly gone as an upstream.  The case for removing this
is less clear than the case for removing the HP-UX docs, but
it still feels like clutter in this document.

Change-Id: Ib7e9bfc8f7ae8e08e9f12b70d5df615496f57bb6
Reviewed-on: http://gerrit.openafs.org/11575
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: D Brashear <shadow@your-file-system.com>