Fail if options have extra parameters [v2]

Fail if options have extra parameters [v2]

Throw an error if an option has extra parameters; previously they
were silently ignored (see also trac #557)

This feature was discussed on the openvpn-devel mailing list
(http://thread.gmane.org/gmane.network.openvpn.devel/9599).

The (modified) message "Unrecognized option or missing or extra
parameter(s)" is used except for a few options:

 * The --help option: An extra parameter for --help generates a
   specific error message after showing the syntax message. This
   is done to help a user who tries "--help tls-cipher" or similar,
   hoping to get more information about the "tls-cipher" option.

 * The --dhcp-option option: It has its own similar message, into
   which " or extra" has been inserted.

 * Ten options such as --up that accept a command (instead of a
   path) already detect extra parameters and generate specific
   error messages that mention double-quoting commands which
   contain embedded spaces.

Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <CAEsd45RvRfmqetu-EoFjSdyBk5F9X1K5muPGu-+_+30TMNOU_A@mail.gmail.com>
URL: http://article.gmane.org/gmane.network.openvpn.devel/9783
URL: https://community.openvpn.net/openvpn/ticket/557

Signed-off-by: Gert Doering <gert@greenie.muc.de>