Cannot edit importance, status or assignee after changing project inline

If you change the project for a bug using the inline AJAX editor
widget, then attempt to edit the status, importance or assignee, the
latter will fail. In the case of status and importance, the following
error message is shown:

  The following errors were encountered:
  Server error, please contact an administrator. OOPS ID:<OOPS ID>

In the case of the assignee, the error shown is:

  Internal Server Error

  Traceback (most recent call last):
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/zope.publisher-3.5.6-py2.4.egg/zope/publisher/publish.py", line 133, in publish
      result = publication.callObject(request, obj)
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/lazr.restful-0.9.5-py2.4.egg/lazr/restful/publisher.py", line 157, in callObject
      value = super(
    File "/srv/staging.launchpad.net/staging/launchpad/lib/canonical/launchpad/webapp/publication.py", line 373, in callObject
      return mapply(ob, request.getPositionalArguments(), request)
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/zope.publisher-3.5.6-py2.4.egg/zope/publisher/publish.py", line 108, in mapply
      return debug_call(obj, args)
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/zope.publisher-3.5.6-py2.4.egg/zope/publisher/publish.py", line 114, in debug_call
      return obj(*args)
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/lazr.restful-0.9.5-py2.4.egg/lazr/restful/_resource.py", line 831, in __call__
      result = self.do_PATCH(media_type, representation)
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/lazr.restful-0.9.5-py2.4.egg/lazr/restful/_resource.py", line 1362, in do_PATCH
      return self.applyChanges(changeset)
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/lazr.restful-0.9.5-py2.4.egg/lazr/restful/_resource.py", line 1078, in applyChanges
      field.set(self.entry, value)
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/zope.schema-3.5.4-py2.4.egg/zope/schema/_bootstrapfields.py", line 183, in set
      setattr(object, self.__name__, value)
    File "/srv/staging.launchpad.net/staging/launchpad/eggs/lazr.restful-0.9.5-py2.4.egg/lazr/restful/declarations.py", line 765, in __set__
      getattr(obj.context, self.mutator)(new_value, **params)
    File "/srv/staging.launchpad.net/staging/launchpad/lib/lp/bugs/model/bugtask.py", line 309, in this_is_a_null_bugtask_method
      raise NotImplementedError
  NotImplementedError

At a guess, this seems like the problem is that the URL path for the
bugtask has changed, but the widgets are attempting to use the old
path.

Bug 443217 should/could be fixed at the same time as this one.