[imp] default pylint to off

[mpanarin]

palantir/python-language-server#698

[seagle0128]

It does make sense and looks fine.

[yyoncho]

Merging based on @seagle0128's comment.

[AndreaOrru]

I found that Pylint may still be run by flycheck as the next checker in chain even when you use flake8.

I solved it by doing:

(add-to-list 'flycheck-disabled-checkers 'python-pylint)