old_contents: #! /usr/bin/env python
  
  #   Copyright 2016 WebAssembly Community Group participants
  #
  #   Licensed under the Apache License, Version 2.0 (the "License");
  #   you may not use this file except in compliance with the License.
  #   You may obtain a copy of the License at
  #
  #       http://www.apache.org/licenses/LICENSE-2.0
  #
  #   Unless required by applicable law or agreed to in writing, software
  #   distributed under the License is distributed on an "AS IS" BASIS,
  #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  #   See the License for the specific language governing permissions and
  #   limitations under the License.
  
  import glob
  import json
  import os
  import urllib2
  
  
  STORAGE_BASE = 'https://storage.googleapis.com/wasm-llvm/builds/git/'
  
  
  def download_revision(force_latest):
    name = 'latest' if force_latest else 'lkgr'
    downloaded = urllib2.urlopen(STORAGE_BASE + name).read().strip()
    # TODO: for now try opening as JSON, if that doesn't work then the content is
    #       just a hash. The waterfall is in the process of migrating to JSON.
    info = None
    try:
      info = json.loads(downloaded)
    except:
      pass
    return info['build'] if type(info) == dict else downloaded
  
  
  def download_tar(tar_pattern, directory, revision):
    tar_path = os.path.join(directory, tar_pattern)
    revision_tar_path = tar_path % revision
    if not os.path.isfile(revision_tar_path):
      with open(revision_tar_path, 'w+') as f:
        f.write(urllib2.urlopen(STORAGE_BASE + tar_pattern % revision).read())
    # Remove any previous tarfiles.
    for older_tar in glob.glob(tar_path % '*'):
      if older_tar != revision_tar_path:
        os.path.remove(older_tar)
    return revision_tar_path
  
new_contents: #! /usr/bin/env python
  
  #   Copyright 2016 WebAssembly Community Group participants
  #
  #   Licensed under the Apache License, Version 2.0 (the "License");
  #   you may not use this file except in compliance with the License.
  #   You may obtain a copy of the License at
  #
  #       http://www.apache.org/licenses/LICENSE-2.0
  #
  #   Unless required by applicable law or agreed to in writing, software
  #   distributed under the License is distributed on an "AS IS" BASIS,
  #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  #   See the License for the specific language governing permissions and
  #   limitations under the License.
  
  import glob
  import json
  import os
  import urllib2
  
  
  STORAGE_BASE = 'https://storage.googleapis.com/wasm-llvm/builds/git/'
  
  
  def download_revision(force_latest):
    name = 'latest' if force_latest else 'lkgr'
    downloaded = urllib2.urlopen(STORAGE_BASE + name).read().strip()
    # TODO: for now try opening as JSON, if that doesn't work then the content is
    #       just a hash. The waterfall is in the process of migrating to JSON.
    info = None
    try:
      info = json.loads(downloaded)
    except:
      pass
    return info['build'] if type(info) == dict else downloaded
  
  
  def download_tar(tar_pattern, directory, revision):
    tar_path = os.path.join(directory, tar_pattern)
    revision_tar_path = tar_path % revision
    if not os.path.isfile(revision_tar_path):
      with open(revision_tar_path, 'w+') as f:
        f.write(urllib2.urlopen(STORAGE_BASE + tar_pattern % revision).read())
    # Remove any previous tarfiles.
    for older_tar in glob.glob(tar_path % '*'):
      if older_tar != revision_tar_path:
        os.remove(older_tar)
    return revision_tar_path
  
subject: Fix 'remove' call.