Remove SVN (and dcommit) support from git-cl

tests/post-dcommit-hook-test.sh

-#!/usr/bin/env bash
-
-# Copyright (c) 2012 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-set -e
-
-. ./test-lib.sh
-
-setup_initsvn
-setup_gitsvn
-
-(
-  set -e
-  cd git-svn
-
-  cat > .git/hooks/post-cl-dcommit << _EOF
-#!/usr/bin/env bash
-git branch -m COMMITTED
-_EOF
-  chmod +x .git/hooks/post-cl-dcommit
-
-  git config rietveld.server localhost:1
-  git checkout -q --track -b work
-  echo "some work done" >> test
-  git add test; git commit -q -m "work \
-TBR=foo"
-
-  test_expect_success "dcommitted code" \
-      "$GIT_CL dcommit --no-oauth2 -f --bypass-hooks -m 'dcommit'"
-
-  test_expect_success "post-cl-dcommit hook executed" \
-      "git symbolic-ref HEAD | grep -q COMMITTED"
-)
-SUCCESS=$?
-
-cleanup
-
-if [ $SUCCESS == 0 ]; then
-  echo PASS
-fi