Eliminate or comment empty blocks and switch fallthrough

Eliminate or comment empty blocks and switch fallthrough

These empty blocks are intentional but trigger code checkers and
were pointed out by Trail of Bits in the security audits. Add comments
to them or eliminate them whatever makes more sense.

For fallthrough C23 [1] has a standard way to signal that but we not
adding a C23 feature to our codebase, so use a comment for now.

[1] https://en.cppreference.com/w/c/language/attributes/fallthrough

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20221215190143.2107896-6-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg25735.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>