Document that --push-remove is generally more suitable than --push-reset

Document that --push-remove is generally more suitable than --push-reset

It's a long-standing and well-known problem that --push-reset removes
"critical" options from the push list (like "topology subnet") which
will then lead to non-working client configs.  This can not be
reasonably fixed, because the list of "critical" options depends on
overall server config.

So just document the fact, and point people towards --push-remove as
a more selective tool.

Trac: #29

Signed-off-by: Gert Doering <gert@greenie.muc.de>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: David Sommerseth <davids@openvpn.net>
Message-Id: <20200908111511.9271-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg20899.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit 5fd66510dfdef628fa95f156c5f9d80af9ae1531)