Require git version 1.6.6

Review URL: http://codereview.chromium.org/652125

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@39741 0039d316-1c4b-4281-b951-d872f2087c98

gclient_scm.py

@@ -165,7 +165,7 @@ class GitWrapper(SCMWrapper, scm.GIT):
     if args:
       raise gclient_utils.Error("Unsupported argument(s): %s" % ",".join(args))
 
-    self._CheckMinVersion("1.6")
+    self._CheckMinVersion("1.6.6")
 
     default_rev = "refs/heads/master"
     url, revision = gclient_utils.SplitUrlRevision(self.url)