The Network proxy contains two methods that are mostly there for example
purposes: security_group_allow_ping and security_group_open_port.
They haven't been included in documentation due to missing docstrings,
and they aren't used anywhere in the SDK or within OSC. They're better
off as actual examples in our documentation than being within code that
we need to support throughout the future.
Change-Id: I4c6b47860b0c2b952e50d4b564451780008b631a