If linter is active, check active file 'on_activated'
If linter is active, check active file 'on_activated'

Before this fix, the active file had 0 edits and
therefore its check was aborted because the linter
(correctly) thought it hadn't been edited by the user.

guillermooo/dart-sublime-bundle,guillermooo-forks/dart-sublime-bundle,guillermooo-forks/dart-sublime-bundle,guillermooo/dart-sublime-bundle,guillermooo/dart-sublime-bundle,guillermooo-forks/dart-sublime-bundle,guillermooo/dart-sublime-bundle,guillermooo-forks/dart-sublime-bundle