[FIX] orm.write: avoid miscalculation of parent_left/right when moving multiple records under same parent
[FIX] orm.write: avoid miscalculation of parent_left/right when moving multiple records under same parent

This issue caused the parent_left and parent_right values to be correct
only for the first record being update as part of a batch update on several
children from the same parent. An example of the consequences is the linked
bug 708503.
xrg/openerp-server,xrg/openerp-server