[PATCH 0/2] corner cases with "rev-list --use-bitmap-index -n"

This series fixes two corner-cases I found when using "-n" along with bitmaps. The results do make _some_ sense if you interpret them correctly, but are sufficiently confusing that I think it's worth dealing with. See the commit messages for the gory details.

The good news is that in the first case, we can produce a more sensible answer without spending any extra work.

The bad news is that the second case cannot, and must fall back to a regular traversal. I doubt anybody even cares about this case in practice, though, as "--objects -n" is somewhat nonsensical already (I didn't run across it in practice; I only noticed while I fixing the first one, which I did see in practice).

  [1/2]: rev-list: "adjust" results of "--count --use-bitmap-index -n"
  [2/2]: rev-list: disable bitmaps when "-n" is used with listing objects

-Peff