Fix various cells issues due to object changes

1) Child cell scheduling fails.  The change to use Instance.create() in
child cells broke things.  The instance properties was being overwritten
due to a typo.  I also found a number of other things that need to be
popped out before passing to create_db_entry_for_new_instance().

2) Notification to the API cell was failing.  We cannot pass an object to
instance_update_at_top().

3) When cells is enabled, deleting an instance hits the '_local_delete'
part of code in the API because we don't see the compute node.  There's
a trap in cells_api.py to forward the delete on to child cells, but we
need to make sure not to try to deallocate network in the API cell.

Fixes bug 1216113

Change-Id: Ie989c22cb3b6a1359a0540e60e06fa4153e93476
Merge "Fix various cells issues due to object changes"