Purchase Orders require stock accounting even if parameter is unchecked

[jniles]

As observed in a demo today, creating a purchase order requires that the accounts for the inventory items exist, even if you have disabled the accounting functionality in the stock settings. This is a bug. We should allow people to make purchases without writing transactions if the stock accounting is not set, potentially with a warning.

[lomamech]

Very interesting I will do it when I have less pressure