ZODB Components: Upon migration, Workflow History of ZODB Components must be kept.
Arnaud Fontaine authored
Also, upon installation of bt5s, install WorkflowItem before Components as it
is needed to restore history.

Another solution would have been to validate() ZODB Components automatically
upon bt5 installation but it would mean losing 'modified' state information
and also imply that *all of them* will be validated even if a developer wants
to publish non-validated ZODB Components.
dce6323f