KEA_QUERY4_RAI	hex string of the entire optin 82
KEA_QUERY4_RAI_CIRCUIT_ID hex string of suboption 1
KEA_QUERY4_RAI_REMOTE_ID hex string of suboption 2

It doesn't work for the first build, because dependencies are not yet
generated.  Subsequent builds should work fine in parallel though.

This avoids variable name conflicts and makes it easier to identify
variables coming from the hook.