Automatically add static route for onegate-proxy

[baby-gnu]

Hello.

With the new onegate-proxy in OpenNebula 6.6, I think that contextualisation should add static address if ONEGATE_ENDPOINT point to a link local address:

1. extract ONEGATE_ENDPOINT host
2. if the ONEGATE_ENDPOINT host is a link local address, add a static route

Thanks.

[rsmontero]

Makes total sense, adding for next release. Thanks!

[tinova]

Related to #277