[Minor] Fix style, formatting and naming in BlockManager etc.

This is a precursor to a bigger change. I wanted to separate out the relatively insignificant changes so the ultimate PR is not inflated.

(Warning: this PR is full of unimportant nitpicks)
I looked at the code more closely, and it looks like we do this all over the place. I think the point is that this is a `getLocal*` method, so it's supposed to exist on disk. I think it might actually be good to keep this exception.