Bug 7583: Cancel a receipt

Bug 7583: Cancel a receipt

In acqui/parcel.pl, there is now the possibility to cancel a receipt.
In "Already received" table, just click on "Cancel receipt" and the
order line will go back to pending orders.
If it was a partial receipt, order line is merged to its 'parent' line.
Attached items are modified so that they become attached to the merged
order line.
If AcqCreateItem is 'receiving', attached items are deleted.
If an order line was first partially received, and then completed. You
must cancel the 'parent' order line before cancelling the 'child'.

Signed-off-by: Marc Veron <veron@veron.ch>
The patch behaves like expected, and the feature is really helpfull.

Just a tiny remark about the following message:

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Cannot cancel receipt. Possible reasons :
You are trying to cancel the receipt of an order line whose parent order line is already received. Cancel this parent order line and retry.
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Maybe it would be good
- to explain a little bit more why it happend and re-word the message for non technical people (not everybody understands 'parent' the same way)

- prevent the situation to happen (e.g. forbid order lines to be deleted if they are already received) - but that would be in the scope of an other bug, I think.

I think such things could be fixed in the future during the ongoing work for Acquisitions module. Signing off.