Summary: Ref T12124. After D18134 we accept either "25" or "low" via HTTP parameters and when the field renders as a control, but if the form has a default value for the field but locks or hides it we don't actually run through that logic. Canonicalize both when rendering the control and when using a raw saved default value. Test Plan: - Created a form with "Priority: Low". - Hid the "Priority" field. - Before patch: Tried to create a task, was rebuffed with a (now verbose and helpful, after D18135) error. - Applied patch: things worked. Reviewers: chad, amckinley Reviewed By: amckinley Maniphest Tasks: T12124 Differential Revision: https://secure.phabricator.com/D18142