support option to turn off VERIFY_PEER

The newer version of rest-client has different `VERIFY_PEER` configuration

```
    Ovirt::Service.new(
      :server   => SERVER,
      :port     => PORT,
      :domain   => DOMAIN,
      :username => USERNAME,
      :password => PASSWORD,
      :ssl_verify => false
    )

```


/cc @brandondunne