Fix pylint error in check-webkit-style

Python allows to load user-site libraries by default
$HOME/.local/lib/pythonX.Y/site-packages. But, it causes WebKit's pylint
fail to load proper libraries.

See http://docs.python.org/2/library/site.html
Use same amount of spaces while statement-cont

1: return true &&
2:    false

In line 2, false is called statement-cont in Emacs.
(statement-cont . +) make it use same spaces in statement-cont.