use coverageDir instead of coverage_dir
use coverageDir instead of coverage_dir

Deprecated coverage_dir in grunt-karma-coveralls,
see
<https://github.com/mattjmorrison/grunt-karma-coveralls/commit/c31cbc7541b33ffb53f6c0912f1ad165cbb1fcb0>

summernote/angular-summernote,thomaslhostis/angular-summernote