[FIX] stock: backorder

Do not try to keep the reservation when creating a backorder for two
reasons:
    1) it doesn't make sense since the backordered move will only be
    confirmed while it got some reserved move lines
    2) with badly configured uom's rounding,  it is possible that the
    initial demand of the backorder is inferior to the now reserved
    quantity

We also fix another "cannot unreserve more than available" cause that
could happen in the second case ; let's imagine in the second case that
the backordered quantity is 0.999, `_update_reserved_qty` will reserve
0.999 on the quants but do not create a move line as range (0, 0.999)
will not return anything.

We remove `test_split_1` as it tested a behavior we removed and add a
new test showing a new flow with what we fixed.

Please note that setting the rounding of unit to 1.0 would have
prevented all the issues here.

0 files changed, 0 insertions, 0 deletions