When the "original" implementation of "create a host via curl" was done in 57d95c1685f28e0a52bd40fc26dd66d24adc0288, the create_host_curl method contained "build": "false", "managed": "false" in the payload, as this is IMHO the correct thing to do (the host is already created, so build:false is obvious, managed:false also makes sense as we do not submit enough data to create a fully managed host).

this also matches the behaviour of bootstrap.py:
https://github.com/Katello/katello-client-bootstrap/blob/master/bootstrap.py#L926
https://github.com/Katello/katello-client-bootstrap/blob/master/bootstrap.py#L936-L939

Now when things were split up into "plain Foreman" and "Foreman with Katello" in 2110556a713d53d5f09f8af35016ee92f0403572, the Katello part is missing the build:false and managed:false entries

This means that every host registration in Katello now needs to flip the machine back to "it's built" state, costing precious time during registration.