Ignore environment variables for coffeelint

Summary: According to coffeelint --help, --noconfig ignores the environment variable COFFEELINT_CONFIG. This means that arc lint will behave more consistently across developer workstations by forcing configuration to be specified with coffeelint.config instead of with environment variables.

Test Plan: This is mostly theoretical.

Reviewers: Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11196