[PATCH 3 of 6 mergedriver] mergestate: add a constructor that sets up a fresh merge state

[Siddharth Agarwal]

On 11/17/15 16:20, Martin von Zweigbergk wrote:
> When I saw patch 4/6, I was wondering how the merge state got removed 
> from disk. It turns out that ms.reset() does that. So this method 
> (fresh()) *is* a method for performing an action after all, right?

Right, but something like mergestate.reset() returning a new merge state 
sounds really weird to my (admittedly non-native) ears.