Merge branch 'master' into sp/reflog

* master: (90 commits)
  fetch.c: remove an unused variable and dead code.
  Clean up sha1 file writing
  Builtin git-cat-file
  builtin format-patch: squelch content-type for 7-bit ASCII
  CMIT_FMT_EMAIL: Q-encode Subject: and display-name part of From: fields.
  add more informative error messages to git-mktag
  remove the artificial restriction tagsize < 8kb
  git-rebase: use canonical A..B syntax to format-patch
  git-format-patch: now built-in.
  fmt-patch: Support --attach
  fmt-patch: understand old <his> notation
  Teach fmt-patch about --keep-subject
  Teach fmt-patch about --numbered
  fmt-patch: implement -o <dir>
  fmt-patch: output file names to stdout
  Teach fmt-patch to write individual files.
  built-in tar-tree and remote tar-tree
  Builtin git-diff-files, git-diff-index, git-diff-stages, and git-diff-tree.
  Builtin git-show-branch.
  Builtin git-apply.
  ...

fetch.h

@@ -28,9 +28,6 @@ extern const char *write_ref;
 /* If set additional text will appear in the ref log. */
 extern const char *write_ref_log_details;
 
-/* If set, the hash that the current value of write_ref must be. */
-extern const unsigned char *current_ref;
-
 /* Set to fetch the target tree. */
 extern int get_tree;