/var/log/ and Directory write permission check - suggestion

Wanted to use the debug logging earlier and so
created .ansible.cfg in home and uncommented

log_path = /var/log/ansible.log

touch /var/log/ansible.log

Thought 660 would be okay for file permission but then hit an error message.

Looked in lib/ansible/callbacks.py

Error message about not writable is not complaining about file permission,
but directory level permission on /var/log

It looks like it this last portion: ... os.access(os.path.dirname(path), os.W_OK):

which suggest need write permission on directory.

Some extra notes in commit comment.

After edit:
...
test_facter (TestRunner.TestRunner) ... SKIP
...
----------------------------------------------------------------------
Ran 83 tests in 20.126s

OK (SKIP=1)

Hope that doing a branch to 'debug_log' before asking for pull request is right way of going about things.