extend sale_exception_nostock to by_line case

In v7, an extra module allowed to select the source location in every
sale order line. In v8 standard, you can select an optional Route in
every line and get the same result.

For that reason, instead of porting the old
sale_exception_nostock_by_line to v8, I extended the
sale_exception_nostock module so that it takes care of the Route
selected if the order line if there is one.
update version, date, authors
skip checks if the source is not internal
delegate the choice of warehouse

While simulating the procurement, the warehouse was chosen from the
order, which is indeed the standard behaviour. I now delegate the
standard method _prepare_order_line_procurement to choose the warehouse.
That way we get a good simulation also when modules like
sale_sourced_by_line change that behaviour.
Merge pull request #47 from lepistone/8.0_sale_exception_nostock_by_line

Extend sale_exception_nostock to by_line case

In v7, an extra module allowed to select the source location in every
sale order line. In v8 standard, you can select an optional Route in
every line and get the same result.
For that reason, instead of porting the old
sale_exception_nostock_by_line to v8, I extended the
sale_exception_nostock module so that it takes care of the Route
selected if the order line if there is one.