Mark ember-concurrency `TaskInstance` errors as benign (#1123)
Mark ember-concurrency `TaskInstance` errors as benign (#1123)

The error messages we are seeing appears to be just expected behavior. We would expect a task to be dropped if a second task is created when one is already running

travis-ci/travis-web,fotinakis/travis-web,fotinakis/travis-web,travis-ci/travis-web,fotinakis/travis-web,travis-ci/travis-web,travis-ci/travis-web,fotinakis/travis-web