Hidden __pycache__ dirs for FilePathField. Refs django#17393.

This will be tested as soon as tests will run under Python 3. Patch taken from Vinay Sajip's Python 3 branch.

Author: claudep

django/forms/fields.py

@@ -932,12 +932,16 @@ def __init__(self, path, match=None, recursive=False, allow_files=True,
  self.choices.append((f, f.replace(path, "", 1)))
  if self.allow_folders:
  for f in dirs:
+ if f == '__pycache__':
+ continue
  if self.match is None or self.match_re.search(f):
  f = os.path.join(root, f)
  self.choices.append((f, f.replace(path, "", 1)))
  else:
  try:
  for f in sorted(os.listdir(self.path)):
+ if f == '__pycache__':
+ continue
  full_file = os.path.join(self.path, f)
  if (((self.allow_files and os.path.isfile(full_file)) or
  (self.allow_folders and os.path.isdir(full_file))) and