Update to git 2.2.0

The difference to the auto generated shears script is
```diff
--- shears-2.2.orig	2014-11-27 18:34:35 +0000
+++ shears-2.2.new	2014-11-27 18:41:52 +0000
@@ -127,11 +127,6 @@
 pick 4b04f46 Config option to disable side-band-64k for transport
 mark t-b/sideband-bug
 
-# Branch: kasal/tests-no-posix
-bud
-pick 9233472 Revert "test: fix t7001 cp to use POSIX options"
-mark kasal/tests-no-posix
-
 # Branch: kblees/kb/fscache-v4-tentative-1.8.5
 rewind hide-dotgit # mingw: add tests for the hidden attribute on the git directory
 pick 33a1078 Win32: make FILETIME conversion functions public
@@ -171,7 +166,6 @@
 merge refs/rewritten/fix-is-exe -C 3d7d03e # Merge 'fix-is-exe' into HEAD
 merge refs/rewritten/msysgit/tip4commit -C 0ac7ef0 # Merge pull request #115 from msysgit/tip4commit
 merge refs/rewritten/t-b/sideband-bug -C 6c55145 # Merge remote-tracking branch 't-b/sideband-bug'
-merge refs/rewritten/kasal/tests-no-posix -C c9ff21b # Merge pull request #181 from kasal/tests-no-posix
 merge refs/rewritten/kblees/kb/fscache-v4-tentative-1.8.5 -C 52591b9 # Merge remote-tracking branch 'kblees/kb/fscache-v4-tentative-1.8.5' into thicket-1.8.5.2
 merge refs/rewritten/kblees/kb/long-paths-v2 -C 53ee2b9 # Merge pull request #122 from kblees/kb/long-paths-v2
 mark kblees/kb/msysgit-2.1.0
```

as we finally have a newer cp.
Additionally I had to fix a few conflicts ( no code changes required).

The test suite reports:
```
Test Summary Report
-------------------
t0050-filesystem.sh                              (Wstat: 0 Tests: 9 Failed: 0)
  TODO passed:   4
t1410-reflog.sh                                  (Wstat: 256 Tests: 15 Failed: 1)
  Failed test:  15
  Non-zero exit status: 1
t3513-revert-submodule.sh                        (Wstat: 0 Tests: 14 Failed: 0)
  TODO passed:   12-14
t3420-rebase-autostash.sh                        (Wstat: 256 Tests: 25 Failed: 6)
  Failed tests:  19-24
  Non-zero exit status: 1
t5000-tar-tree.sh                                (Wstat: 256 Tests: 49 Failed: 1)
  Failed test:  48
  Non-zero exit status: 1
t5503-tagfollow.sh                               (Wstat: 0 Tests: 11 Failed: 0)
  TODO passed:   3, 6, 9
Files=687, Tests=12189, 1401 wallclock secs ( 5.10 usr  6.02 sys + 977.64 cusr 2133.84 csys = 3122.60 CPU)
Result: FAIL
```
I've not yet come up with fixes for the failures and also don't know when I find time for it.