Refactored openvpn::client::passwordauth

Previous implementation was based on a template configuration files and separate
CA cert and TA key. Migrated to a setup where the configuration file is assumed
to be an inline configuration, and the role of openvpn::client::passwordauth is
to just generate the credentials file for autologins.

Signed-off-by: Samuli Seppänen <samuli.seppanen@gmail.com>
Fixed a minor issue in openvpn::client::passwordauth

There was no default value (undef) set for this class.

Signed-off-by: Samuli Seppänen <samuli@openvpn.net>
Updated OpenVPN build dependencies with autoconf, make and libtool

Signed-off-by: Samuli Seppänen <samuli@openvpn.net>