Integration test TLS connection

Adds TLS configuration to OpenLDAP vm for integration testing.

![2014-11-21 at 3 05 pm](https://cloud.githubusercontent.com/assets/19874/5152128/56d91988-719f-11e4-8e70-75e53ff7282b.png)

cc https://github.com/ruby-ldap/ruby-net-ldap/pull/161 @mtodd @schaary