Do not mix OpenVPN's secure modes

As noted in the forum [1] only one OpenVPN secure mode can be specified at a time. In the shared key configuration the secret mode is used. However the generated configuration also includes the "client" option which is an alias/shortcut for "pull" and "tls-client", where "tls-client" is another secret mode.

The patch removes the "client" alias and replaces it with the "pull" option only.

[1] http://forum.pfsense.org/index.php/topic,58180.0.html