message: Fix failure in get_filecheck_path when filecheck is None
  If the path was not specified (and it's None), lexists throws an exception rather than returning False. get_filecheck_path now checks whether filecheck is set before calling lexists
diff: @@ -188,5 +188,5 @@ def get_filecheck_path():
  """
  Get the path to the FileCheck testing tool.
  """
  - if os.path.lexists(filecheck):
  + if filecheck and os.path.lexists(filecheck):
  return filecheck
  