store: cleanup what is recognized as a revlog file The temporary file from `censor` are not relevant to the store as they are just temporary. So let `fncache` and `datafiles` forget about them.

store: only inclure revlog related file in `datafiles` This is a "reading" equivalent of the previous patches (see that patch for details).

store: do not record file that are not part of a revlog in fncache The fncache exist to list file to copy/stream when cloning a repository, it should only contains file that are relevant for a revlog in such case. For example, temporary file are not relevant. So we now skip the addiction of non-relevant file to the fn-cache in the first place.