Fix flickering when dragging over child element
Fix flickering when dragging over child element

If dragged over the child element, the dz-drag-hover class is removed. See enyo/dropzone#438 for more info.

It's unlikely this problem will be fixed in the core of dropzonejs soon, so applied the fix made by @jhubert. Code can be deleted as soon dropzonjs team fixes this.
vladucu/ember-cli-dropzonejs,vladucu/ember-cli-dropzonejs,FutoRicky/ember-cli-dropzonejs,jakeleboeuf/ember-cli-dropzonejs,FutoRicky/ember-cli-dropzonejs,jakeleboeuf/ember-cli-dropzonejs