Ignore auth-nocache for auth-user-pass if auth-token is pushed

Ignore auth-nocache for auth-user-pass if auth-token is pushed

When the auth-token option is pushed from the server to the client,
the latter has to ignore the auth-nocache directive (if specified).

The password will now be substituted by the unique token, therefore
it can't be wiped out, otherwise the next renegotiation will fail.

Trac: #840
Cc: David Sommerseth <openvpn@sf.lists.topphemmelig.net>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <20170225004014.28638-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg14194.html
Signed-off-by: David Sommerseth <davids@openvpn.net>