changelog-delay: move the delay/divert logic inside the (inner) revlog...
changelog-delay: move the delay/divert logic inside the (inner) revlog
Instead of hacking throught the vfs/opener, we implement the delay/divert logic
inside the `_InnerRevlog` and `randomaccessfile` object. This will allow to an
alternative implementation of the `_InnerRevlog` that does not need to use Python details.
As a result, the new implementation can use the transaction less agressively
and avoid some extra output since no data had been written yet. That seems like
a good side effect.
