[FIX] account: performance improvement on analytic line creation
 remove analytic lines (to avoid duplicates) only when create new one instead of each validation of the account move
don't create new analytic lines at move creation, will do it once the move is balanced (unbalanced move should not create analytic lines yet)
[FIX] purchase: warning uom category different only if the changed field is product_uom itself.

Changing product_id with a different unit category does not trigger the uom category change warning
[MERGE] [FIX] account: performance improvement on account.analytic.lines
don't create new analytic lines at move creation, will do it once the move is balanced
don't remove analytic lines (to avoid duplicates) at the begining of the validation of a move, will do it once we create the new correct analytic lines (opw 597719)