- Can now call make_transient() on an instance that

- Can now call make_transient() on an instance that
is referenced by parent objects via many-to-one,
without the parent's foreign key value getting
temporarily set to None - this was a function
of the "detect primary key switch" flush handler.
It now ignores objects that are no longer
in the "persistent" state, and the parent's
foreign key identifier is left unaffected.