Make code and documentation for --remote-random-hostname consistent.

Documentation examples, description and code were disagreeing on what
this option actually does.  Now they will all agree that it will
*prepend* a random-byte string to the hostname name before resolving
to work around DNS caching (needs a "*" wildcard record in the zone).

Fix trac #143

Signed-off-by: Gert Doering <gert@greenie.muc.de>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <1384698620-27946-1-git-send-email-gert@greenie.muc.de>
URL: http://article.gmane.org/gmane.network.openvpn.devel/7999
(cherry picked from commit 7de8f3f322c1a1c13022a0243267624930dac5c9)