Homu chooses the wrong commit

[Ryman]

E.g. nickel-org/nickel.rs#267 (comment)

Homu is choosing a non-existing commit (which looks a lot like a null value somewhere) of 0000000 and nothing seems to happen. On the queue it is still listed as approved.

There has been squashing and rebasing on the branch, if that's of any concern?

[Ryman]

This was fixed :)