[PATCH 0/4] git replace --edit --raw

I tried to use "git replace --edit" today to repair a corrupted tree that had an empty filename:

  $ git replace --edit HEAD^{tree}
  fatal: empty filename in tree entry
  fatal: cat-file reported failure

Oops. One of the major purposes of the command is to repair broken objects. This series introduces a "--raw" option to let you easily edit the binary if need be.

The first two patches are unrelated cleanups I noticed in the area. The third is refactoring, and the final one is the interesting bit.

There's a minor textual conflict in the documentation with cc/replace-graft, but it's pretty straightforward to resolve.

  [1/4]: replace: replace spaces with tabs in indentation
  [2/4]: avoid double close of descriptors handed to run_command
  [3/4]: replace: use argv_array in export_object
  [4/4]: replace: add a --raw mode for --edit

-Peff