Freeze netd AIDL interface (framework)

This freezes the interface as of the latest beta build, although it has
not changed since then.
This change adds the necessary implementations for getInterfaceVersion.

Test: flashed, WiFi working
Bug: 128803828
Change-Id: I43a6a38685d5fbc669cd573c4d7e7f99bd596952
2 files changed