Move repository.CloneGitRepo to git.Clone

The existing git.Clone was replaced with a slightly updated version of
repository.CloneGitRepo and callers of CloneGitRepo were updated.

BUG=none
TEST=./run_tests --network lib/git_unittest \
         cbuildbot/{lkgm_manager,manifest_version,repository}_unittest

Change-Id: I4a0eb7ac968125b9991133c1ab20cd638ce409bf
Reviewed-on: https://chromium-review.googlesource.com/1178751
Commit-Ready: Lann Martin <lannm@chromium.org>
Tested-by: Lann Martin <lannm@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_merge_to_branch.py b/scripts/cros_merge_to_branch.py
index e11d928..24e5ea8 100644
--- a/scripts/cros_merge_to_branch.py
+++ b/scripts/cros_merge_to_branch.py
@@ -167,7 +167,7 @@
     if not email:
       email = git.GetProjectUserEmail(reference)
 
-  repository.CloneGitRepo(work_dir, patch.project_url, reference=reference)
+  git.Clone(work_dir, patch.project_url, reference=reference)
 
   # Set the git committer.
   git.RunGit(work_dir, ['config', '--replace-all', 'user.email', email])