Cleanup from any previous installer enough for _CheckInstallSuccess.

def _CleanupInstall(self):
    """Cleanup from any previous installer enough for _CheckInstallSuccess."""
    if os.path.exists(self.install_path):
      shutil.rmtree(self.install_path)
      if os.path.exists(self.install_path):
        raise RuntimeError("Install path still exists: %s" % self.install_path)

    # Deliberately don't check return code, since service may not be installed.
    subprocess.call(["sc", "stop", self.service_name])