Fix Plugin-Outlets: remove block from views so Ember doesn't complain

When you are adding a plugin-outlet with a block like ``{{#plugin-outlet blockname}}<h1>hello</h2>{{/plugin-outlet}}`` and have a plugin overwrite it Ember complains saying `You cannot provide a template block if you also specified a templateName` and stops the entire application.

This patch removes the block-function in case we've found ourself replacing it with a view to prevent ember from complaining both are given.