Distribution owners can't enable blueprints

Its not possible for a distribution owner to enable blueprints. The issue stems from that right requires Admin, not Registrant. Backtrace from Dogfood.

Traceback (innermost last):

    * Module zope.publisher.publish, line 138, in publish
      result = publication.callObject(request, object)
    * Module canonical.launchpad.webapp.publication, line 332, in callObject
      return mapply(ob, request.getPositionalArguments(), request)
    * Module zope.publisher.publish, line 113, in mapply
      return debug_call(object, args)
      __traceback_info__: <security proxied zope.app.pagetemplate.simpleviewclass.SimpleViewClass from /srv/launchpad.net/codelines/2.1.9/lib/canonical/launchpad/templates/distribution-edit.pt instance at 0x428cb34c>
    * Module zope.publisher.publish, line 119, in debug_call
      return object(*args)
    * Module canonical.launchpad.webapp.publisher, line 219, in __call__
      self.initialize()
    * Module canonical.launchpad.webapp.launchpadform, line 108, in initialize
      self.form_result = action.success(data)
    * Module zope.formlib.form, line 569, in success
      return self.success_handler(self.form, self, data)
    * Module canonical.launchpad.browser.distribution, line 756, in change_action
      self.updateContextFromData(data)
    * Module canonical.launchpad.webapp.launchpadform, line 383, in updateContextFromData
      data, self.adapters)
    * Module zope.formlib.form, line 496, in applyChanges
      field.set(adapter, newvalue)
    * Module zope.schema._bootstrapfields, line 325, in set
      Field.set(self, object, value)
    * Module zope.schema._bootstrapfields, line 183, in set
      setattr(object, self.__name__, value)

Unauthorized: (<Distribution at 0x461625ec>, 'official_blueprints', 'launchpad.Admin')