Fix flaky test

[keorn]

and clean up chain specs.

[coveralls]

Changes Unknown when pulling 959ccc7 on fix-flaky-auth into ** on master**.

[rphmeier]

What does the rlp member mean for a generic-family engine?
(just a question about the changes to the spec file, tangential to the PR itself)

[keorn]

Its just the genesis block seal. So these just change the initial value of seal fields to 0.

[rphmeier]

interesting...why not use a JSON array and enforce the length to be equal to the field amount? seems a bit more flexible/tweakable than having to re-encode RLP to make changes

[keorn]

That's how it was.
I think it might be best to get rid of "fields" (redundant) and just have the RLP field which has to be a valid list (then it is compatible with whatever the seal generating function outputs, not requiring partial decoding). Also new seal type can be added if there is a new prominent Engine.