[FIX] account: reconcile: no useless revalidation

Avoid revalidating the complete account moves
that contain the lines being reconciled.
The reconciliation does not change the validity
of those moves anyway.
This represents a very important speed up of
reconciliation when moves with several hundred
lines are involved.
[FIX] stock: inventory lines with no production lot: compare with correct stock level

Inventory lines without production lot number should
be compared with the stock level of products without
a production lot. Otherwise the final result of a
validated inventory is wrong as soon as there are
lines with and without production lot for the same
product.

Adds corresponding regression test.

Fixes https://bugs.launchpad.net/openobject-addons/+bug/1008099
Manual rebase of #1658, courtesy of Numerigraphe
Merge branch '7.0' of https://github.com/odoo/odoo into 7.0-linux64