emberjs/data — pull request #117 by vr-pair (2012-02-24 00:19:47+00:00)
Title: Allowing errors to be undefined

When we bind to an error property in the view, it sets the
value to undefined. This causes the errors to not be an empty
object, thus the model never transitions out of invalid.

Also deleted our least prefered version of isEmptyObject,
since having two did not seem necessary.