Revert "Add new @ shortcut for HEAD"

This reverts commit cdfd94837b27c220f70f032b596ea993d195488f, as it
does not just apply to "@" (and forms with modifiers like @{u}
applied to it), but also affect e.g. "refs/heads/@/foo" which it
shouldn't.

The topic can be retried later, but let's revert to avoid affecting
existing use cases for now.
Merge branch 'km/svn-1.8-serf-only' into jch

Subversion 1.8.0 that was recently released breaks older subversion
clients coming over http/https in various ways.

* km/svn-1.8-serf-only:
  Git.pm: revert _temp_cache use of temp_is_locked
  git-svn: allow git-svn fetching to work using serf
  Git.pm: add new temp_is_locked function
Merge branch 'jc/check-x-z' into jch

"git check-ignore -z" applied the NUL termination to both its input
(with --stdin) and its output, but "git check-attr -z" ignored the
option on the output side.

This is potentially a backward incompatible fix.  I am tempted to
merge this to and keep it in 'next' for a while to see if anybody
screams before deciding if we want to do anything to help existing
users (there may be none).

* jc/check-x-z:
  check-attr -z: a single -z should apply to both input and output
  check-ignore -z: a single -z should apply to both input and output
  check-attr: the name of the character is NUL, not NULL
  check-ignore: the name of the character is NUL, not NULL

# Conflicts:
# 	builtin/check-ignore.c
Merge branch 'ms/fetch-prune-configuration' into jch

Allow fetch.prune and remote.*.prune configuration variables to be set,
and "git fetch" to behave as if "--prune" is given.

"git fetch" that honors remote.*.prune is fine, but I wonder if we
should somehow make "git push" aware of it as well.  Perhaps
remote.*.prune should not be just a boolean, but a 4-way "none",
"push", "fetch", "both"?

* ms/fetch-prune-configuration:
  fetch: make --prune configurable
Merge branch 'rj/doc-rev-parse' into jch

* rj/doc-rev-parse:
  rev-parse(1): logically group options
  rev-parse: remove restrictions on some options
Merge branch 'jc/pull-training-wheel' into jch

Make "git pull" (without arguments that say what branch to
integrate from where) refuse with "it does not fast forward; choose
between 'pull --merge' and 'pull --rebase'".

See

http://thread.gmane.org/gmane.comp.version-control.git/225146/focus=225326
http://thread.gmane.org/gmane.comp.version-control.git/225146/focus=229221

for full discussion.

* jc/pull-training-wheel:
  pull: require choice between rebase/merge on non-fast-forward pull
Merge branch 'jc/diff-filter-negation' into jch

Teach "git diff --diff-filter" to express "I do not want to see
these classes of changes" more directly by listing only the
unwanted ones in lowercase (e.g. "--diff-filter=d" will show
everything but deletion) and deprecate "diff-files -q" which did
the same thing as "--diff-filter=d".

* jc/diff-filter-negation:
  diff: deprecate -q option to diff-files
  diff: allow lowercase letter to specify what change class to exclude
  diff: reject unknown change class given to --diff-filter
  diff: preparse --diff-filter string argument
  diff: factor out match_filter()
  diff: pass the whole diff_options to diffcore_apply_filter()

# Conflicts:
# 	diff.c
Merge branch 'jk/fast-import-empty-ls' into jch

* jk/fast-import-empty-ls:
  fast-import: allow moving the root tree
  fast-import: allow ls or filecopy of the root tree
  fast-import: set valid mode on root tree in "ls"
  t9300: document fast-import empty path issues
Merge branch 'nd/magic-pathspec' into jch

Use "struct pathspec" interface in more places, instead of array of
characters, the latter of which cannot express magic pathspecs
(e.g. ":(icase)makefile" that matches both Makefile and makefile).

* nd/magic-pathspec: (48 commits)
  rm: do not set a variable twice without intermediate reading.
  t6131 - skip tests if on case-insensitive file system
  parse_pathspec: accept :(icase)path syntax
  pathspec: support :(glob) syntax
  pathspec: make --literal-pathspecs disable pathspec magic
  pathspec: support :(literal) syntax for noglob pathspec
  kill limit_pathspec_to_literal() as it's only used by parse_pathspec()
  parse_pathspec: preserve prefix length via PATHSPEC_PREFIX_ORIGIN
  parse_pathspec: make sure the prefix part is wildcard-free
  rename field "raw" to "_raw" in struct pathspec
  tree-diff: remove the use of pathspec's raw[] in follow-rename codepath
  remove match_pathspec() in favor of match_pathspec_depth()
  remove init_pathspec() in favor of parse_pathspec()
  remove diff_tree_{setup,release}_paths
  convert common_prefix() to use struct pathspec
  convert add_files_to_cache to take struct pathspec
  convert {read,fill}_directory to take struct pathspec
  convert refresh_index to take struct pathspec
  convert report_path_error to take struct pathspec
  checkout: convert read_tree_some to take struct pathspec
  ...
Merge branch 'jc/push-cas' into jch

Allow a safer "rewind of the remote tip" push than blind "--force",
by requiring that the overwritten remote ref to be unchanged since
the new history to replace it was prepared.

The machinery is more or less ready.  The "--force" option is again
the big red button to override any safety, thanks to J6t's sanity
(the original round allowed --lockref to defeat --force).

The logic to choose the default implemented here is fragile
(e.g. "git fetch" after seeing a failure will update the
remote-tracking branch and will make the next "push" pass,
defeating the safety pretty easily).  It is suitable only for the
simplest workflows, and it may hurt users more than it helps them.

* jc/push-cas:
  push: teach --force-with-lease to smart-http transport
  send-pack: fix parsing of --force-with-lease option
  t5540/5541: smart-http does not support "--force-with-lease"
  t5533: test "push --force-with-lease"
  push --force-with-lease: tie it all together
  push --force-with-lease: implement logic to populate old_sha1_expect[]
  remote.c: add command line option parser for "--force-with-lease"
  builtin/push.c: use OPT_BOOL, not OPT_BOOLEAN
  cache.h: move remote/connect API out of it

# Conflicts:
# 	remote-curl.c
# 	remote.c
Merge branch 'nd/clone-connectivity-shortcut' into jch

* nd/clone-connectivity-shortcut:
  smart http: use the same connectivity check on cloning

# Conflicts:
# 	remote-curl.c
Merge branch 'rr/feed-real-path-to-editor' into jch

* rr/feed-real-path-to-editor:
  editor: use canonicalized absolute path
Merge branch 'db/http-savecookies' into jch

* db/http-savecookies:
  t5551: Remove header from curl cookie file
  http: add http.savecookies option to write out HTTP cookies
Merge branch 'nd/sq-quote-buf' into jch

Code simplification as a preparatory step to something larger.

* nd/sq-quote-buf:
  quote: remove sq_quote_print()
  tar-tree: remove dependency on sq_quote_print()
  for-each-ref, quote: convert *_quote_print -> *_quote_buf
Merge branch 'da/darwin' into jch

* da/darwin:
  OS X: Fix redeclaration of die warning
  Makefile: Fix APPLE_COMMON_CRYPTO with BLK_SHA1
  imap-send: use Apple's Security framework for base64 encoding
Merge branch 'mb/docs-favor-en-us' into jch

Declare that the official grammar & spelling of the source of this
project is en_US, but strongly discourage patches only to "fix"
existing en_UK strings to avoid unnecessary churns.

* mb/docs-favor-en-us:
  Provide some linguistic guidance for the documentation.
Merge branch 'bc/unuse-packfile' into jch

Handle memory pressure and file descriptor pressure separately when
deciding to release pack windows to honor resource limits.

* bc/unuse-packfile:
  Don't close pack fd when free'ing pack windows
  sha1_file: introduce close_one_pack() to close packs on fd pressure
Merge branch 'es/blame-L-more' into jch

More fixes to the code to parse the "-L" option in "log" and "blame".

* es/blame-L-more:
  blame: reject empty ranges -L,+0 and -L,-0
  t8001/t8002: blame: demonstrate acceptance of bogus -L,+0 and -L,-0
  blame: reject empty ranges -LX,+0 and -LX,-0
  t8001/t8002: blame: demonstrate acceptance of bogus -LX,+0 and -LX,-0
  log: fix -L bounds checking bug
  t4211: retire soon-to-be unimplementable tests
  t4211: log: demonstrate -L bounds checking bug
  blame: fix -L bounds checking bug
  t8001/t8002: blame: add empty file & partial-line tests
  t8001/t8002: blame: demonstrate -L bounds checking bug
  t8001/t8002: blame: decompose overly-large test
Merge branch 'jk/cat-file-batch-optim' into jch

Rework the reverted change to `cat-file --batch-check`.

* jk/cat-file-batch-optim:
  cat-file: only split on whitespace when %(rest) is used
Merge branch 'jc/parseopt-command-modes' into jch

Many commands use --dashed-option as a operation mode selector
(e.g. "git tag --delete") that the user can use at most one
(e.g. "git tag --delete --verify" is a nonsense) and you cannot
negate (e.g. "git tag --no-delete" is a nonsense).  Make it easier
for users of parse_options() to enforce these restrictions.

* jc/parseopt-command-modes:
  tag: use OPT_CMDMODE
  parse-options: add OPT_CMDMODE()