This changes the response to match lorax-composer's behavior. If any of
the blueprints in the list passed to /blueprints/depsolve/... have an
error that error should be appended to the error list, and the blueprint
included in the blueprints list with an empty dependencies section.
It was returning an error 400 and a single error if it hit any depsolve
problems, skipping any other blueprints and returning the wrong
response.
This also adjusts the tests to account for the change.
Fixes#890
eb76b9ec8e