Remove empty dummy functions

Remove empty dummy functions

These functions seem to have been added to avoid MSVC compiler warnigns.
However nowadays, they trigger compiler warnings from Clang (e.g. when
using --disable-lzo and --disable-lz4):

src/openvpn/fdmisc.c
/Users/arne/oss/openvpn-git/src/openvpn/comp-lz4.c:315:1: error: unused
function 'dummy' [-Werror,-Wunused-function]
dummy(void)
^
1 error generated.

Testing with MSVC shows that removing these functions does not trigger
warnings with MSVC either.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20210322102119.14322-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg21787.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>