This fixes a performance regression introduced in
commit 0a8fbb36
("Simulation: index 'delivery' categories in ZODB")

Built delivery lines are modified by newContent(), before
SimulatedDeliveryBuilder._setDeliveryMovementProperties() has a chance to set
the delivery link on the related simulation movement.
So isGeneratedBySimulation() always returned False.

One solution was to revert all changes in
  product/ERP5/Document/Movement.py
  product/ERP5/Document/SimulatedDeliveryBuilder.py
from the aforementioned commit, but it's much simpler to move the interaction
at the end of the transaction, even if in some rare cases, 2 '_updateSimulation'
activities are created, causing a slight overhead on activity tool.
Signed-off-by: Kazuhiko Shiozaki <kazuhiko@nexedi.com>