Update bleeding edge version of git on windows to 2.8.3.

TBR=nodir@chromium.org
BUG=600028

Review URL: https://codereview.chromium.org/2010573004 .

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300664 0039d316-1c4b-4281-b951-d872f2087c98

bootstrap/win/win_tools.bat

@@ -70,7 +70,7 @@ reg Query "HKLM\Hardware\Description\System\CentralProcessor\0" | %FIND_EXE% /i
 if not exist "%WIN_TOOLS_ROOT_DIR%\.git_bleeding_edge" (
   set GIT_VERSION=2.7.4
 ) else (
-  set GIT_VERSION=2.8.1
+  set GIT_VERSION=2.8.3
 )
 set GIT_VERSION=%GIT_VERSION%-%OS_BITS%