Document comp-lzo no and compress being incompatible

Document comp-lzo no and compress being incompatible

Most of the new compress but not v2 version do use swap operation. For
'compress lzo' the swap option is not used for backwards compatibility.
For lz4 the swap option is also not a problem since there is no version
without swap. Unfortunately, compress introduced a second stub format
with swap, contrary to the one in 'comp-lzo no' that does not use swap.

Document this weirdness to let not others fall into this trap.

v2: redo patch for rst man pages

Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20200811110248.3396-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg20708.html

Signed-off-by: Gert Doering <gert@greenie.muc.de>