add failing test for clearing date
add failing test for clearing date

SquireLabs/ember-datepicker,brendan-rius/ember-datepicker,jeffhertzler/ember-datepicker,jeffhertzler/ember-datepicker,SquireLabs/ember-datepicker,brendan-rius/ember-datepicker,brendan-rius/ember-datepicker,SquireLabs/ember-datepicker,jeffhertzler/ember-datepicker