The cleanup of the JavaScript page models/views moved

RB.ReviewabePageView.reviewRequest into the model as an attribute.

This breaks Power Pack, which expects this attribute to exist.
While we will want to update Power Pack to optimistically use the new

attribute, we don't want to break existing installs of Power Pack when

people upgrade. This restores the attribute for compatibility with a

comment explaining the situation.

Tested that PDF document review worked again.