Log Message:
Changes 1.8.4.2:
* "git clone" gave some progress messages to the standard output, not
  to the standard error, and did not allow suppressing them with the
  "--no-progress" option.
* "format-patch --from=<whom>" forgot to omit unnecessary in-body
  from line, i.e. when <whom> is the same as the real author.
* "git shortlog" used to choke and die when there is a malformed
  commit (e.g. missing authors); it now simply ignore such a commit
  and keeps going.
* "git merge-recursive" did not parse its \ 
"--diff-algorithm=" command
  line option correctly.
* "git branch --track" had a minor regression in v1.8.3.2 and later
  that made it impossible to base your local work on anything but a
  local branch of the upstream repository you are tracking from.
* "git ls-files -k" needs to crawl only the part of the working tree
  that may overlap the paths in the index to find killed files, but
  shared code with the logic to find all the untracked files, which
  made it unnecessarily inefficient.
* When there is no sufficient overlap between old and new history
  during a "git fetch" into a shallow repository, objects that the
  sending side knows the receiving end has were unnecessarily sent.
* When running "fetch -q", a long silence while the sender side
  computes the set of objects to send can be mistaken by proxies as
  dropped connection.  The server side has been taught to send a
  small empty messages to keep the connection alive.
* When the webserver responds with "405 Method Not Allowed", "git
  http-backend" should tell the client what methods are allowed with
  the "Allow" header.
* "git cvsserver" computed the permission mode bits incorrectly for
  executable files.
* The implementation of "add -i" has a crippling code to work around
  ActiveState Perl limitation but it by mistake also triggered on Git
  for Windows where MSYS perl is used.
* We made sure that we notice the user-supplied GIT_DIR is actually a
  gitfile, but did not do the same when the default ".git" is a
  gitfile.
* When an object is not found after checking the packfiles and then
  loose object directory, read_sha1_file() re-checks the packfiles to
  prevent racing with a concurrent repacker; teach the same logic to
  has_sha1_file().
* "git commit --author=$name", when $name is not in the canonical
  "A. U. Thor <au.thor@example.xz>" format, looks for a matching name
  from existing history, but did not consult mailmap to grab the
  preferred author name.
* The commit object names in the insn sheet that was prepared at the
  beginning of "rebase -i" session can become ambiguous as the
  rebasing progresses and the repository gains more commits. Make
  sure the internal record is kept with full 40-hex object names.
* "git rebase --preserve-merges" internally used the merge machinery
  and as a side effect, left merge summary message in the log, but
  when rebasing, there should not be a need for merge summary.
* "git rebase -i" forgot that the comment character can be
  configurable while reading its insn sheet.