autotools: Fix wrong ./configure help screen default values

autotools: Fix wrong ./configure help screen default values

enable_crypto_ofb_cfb is "yes" by default, so the --help screen
should show --disable-ofb-cfb and not --enable-ofb-cfb.

enable_small and enable_password_save are both "no" by default, so
the --help screen should state "default: no".  Now it says "yes" as
default, but is really disabled in the reality.

Signed-off-by: David Sommerseth <davids@redhat.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1416852578-7581-1-git-send-email-openvpn.list@topphemmelig.net>
URL: http://article.gmane.org/gmane.network.openvpn.devel/9278
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit 104360b4f40a4ba29987d9478aed70450fec75a2)