Trac #15468: update to latest upstream git

The git self-tests fail on OSX 10.8, 10.9 because of braindamage in
Apple's regex library. This is worked around in upstream git, so just
update to the latest and greatest:
{{{
*** t0070-fundamental.sh ***
ok 1 - character classes (isspace, isalpha etc.)
ok 2 - mktemp to nonexistent directory prints filename
ok 3 - mktemp to unwritable directory prints filename
not ok - 4 check for a bug in the regex routines
#
#               # if this test fails, re-build git with NO_REGEX=1
#               test-regex
#
# failed 1 among 4 test(s)
1..4
make[5]: *** [t0070-fundamental.sh] Error 1
make[4]: *** [test] Error 2
make[3]: *** [test] Error 2
Error running git's combined build/test suite.
}}}

Upstream tarball:
https://www.kernel.org/pub/software/scm/git/git-1.8.4.4.tar.bz2

URL: http://trac.sagemath.org/15468
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s): R. Andrew Ohana

build/pkgs/git/checksums.ini

@@ -1,3 +1,3 @@
-sha1=8cce24a390595d6e62c3aa66bef332ab95900173
-md5=9b178a549f64e6f896b634e76ce4c1a6
-cksum=3835145085
+sha1=8640f3c97a93b7b7788147f6eef1097b24192b2b
+md5=cfeec35a50177d3aecdb15f1e89a55cc
+cksum=4106921953

build/pkgs/git/package-version.txt

@@ -1 +1 @@
-1.7.12.2.p0
+1.8.4.4

src/sage/dev/git_interface.py

@@ -215,20 +215,13 @@ def _execute(self, cmd, *args, **kwds):
             GitError: git returned with non-zero exit code (129) for
             "git -c user.email=doc@test.test -c user.name=doctest status --foo".
             output to stderr: error: unknown option `foo'
-             usage: git status [options] [--] <filepattern>...
+             usage: git status [options] [--] ...
             <BLANKLINE>
                  -v, --verbose         be verbose
                  -s, --short           show status concisely
                  -b, --branch          show branch information
                  --porcelain           machine-readable output
-                 -z, --null            terminate entries with NUL
-                 -u, --untracked-files[=<mode>]
-                                       show untracked files, optional modes: all, normal, no. (Default: all)
-                 --ignored             show ignored files
-                 --ignore-submodules[=<when>]
-                                       ignore changes to submodules, optional when: all, dirty, untracked. (Default: all)
-                 --column[=<style>]    list untracked files in columns
-            <BLANKLINE>
+            ...
         """
         exit_code, stdout, stderr, cmd = self._run_git(cmd, args, kwds)
         if exit_code:
@@ -262,20 +255,13 @@ def _execute_silent(self, cmd, *args, **kwds):
             GitError: git returned with non-zero exit code (129) for
             "git -c user.email=doc@test.test -c user.name=doctest status --foo".
             output to stderr: error: unknown option `foo'
-             usage: git status [options] [--] <filepattern>...
+             usage: git status [options] [--] ...
             <BLANKLINE>
                  -v, --verbose         be verbose
                  -s, --short           show status concisely
                  -b, --branch          show branch information
                  --porcelain           machine-readable output
-                 -z, --null            terminate entries with NUL
-                 -u, --untracked-files[=<mode>]
-                                       show untracked files, optional modes: all, normal, no. (Default: all)
-                 --ignored             show ignored files
-                 --ignore-submodules[=<when>]
-                                       ignore changes to submodules, optional when: all, dirty, untracked. (Default: all)
-                 --column[=<style>]    list untracked files in columns
-            <BLANKLINE>
+            ...
         """
         exit_code, stdout, stderr, cmd = self._run_git(cmd, args, kwds)
         if exit_code:
@@ -758,14 +744,12 @@ def clean_wrapper(self, remove_untracked_files=False,
 
             sage: git.clean_wrapper(remove_untracked_files=True)
             Removing untracked
-            Not removing untracked_dir/
             sage: git.clean_wrapper(
             ....:     remove_untracked_files=True, remove_untracked_directories=True)
             Removing untracked_dir/
             sage: git.clean_wrapper(
             ....:     remove_untracked_files=True, remove_ignored=True)
             Removing ignored
-            Not removing ignored_dir/
             sage: git.clean_wrapper(
             ....:     remove_untracked_files=True,
             ....:     remove_untracked_directories=True,