sockets: Remove the limitation of --tcp-nodelay to be server-only

The assert(0) happening if trying to use --tcp-nodelay in a client
config is really not helpful at all.  When this assert(0) was removed,
another warning appeared that this could only be used in server
configs.  That itself is also quite silly, as clients can choose to
use --socket-flags TCP_NODELAY in the client config instead.  This
behaviour does not help the user in any way.

This patch removes the server-only restriction and rather provides
a more helpful warning when using --tcp-nodelay on the client side.

Trac: 489
Signed-off-by: David Sommerseth <davids@redhat.com>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: 1418118764-17846-1-git-send-email-openvpn.list@topphemmelig.net
URL: http://article.gmane.org/gmane.network.openvpn.devel/9334