[16.0][IMP] purchase_order_supplierinfo_update : also synchronize discount from PO lines to supplierinfo (and other fields)

[arnaudlayec]

It can be useful to synchronize other fields from PO lines to supplierinfo prices, like discount from the module purchase_discount or discount1/2/3 from purchase_discount_triple.
This update allow it without hard dependency with such modules purchase_discount or purchase_discount_triple by verifying if the field exists in PO lines and supplierinfo models before trying to write it.

Finally the method _get_synch_fields_line_to_supplierinfo() can be inherited to add other fields to synchronize from PO lines to supplierinfo.

[OCA-git-bot]

Hi @ernestotejeda,
some modules you are maintaining are being modified, check this out!

[legalsylvain]

some review inline.

[legalsylvain]

FYI : here are other pending refactoring, that could be interesting for you :

• [REF] purchase_triple_discount : move triple.discount.mixin in account_invoice_triple_discount module. (OCA/account-invoicing) #2686
• [REF] account_invoice_triple_discount : integrate triple.discount.mixin, previously in purchase_triple_discount module. (OCA/purchase-workflow) account-invoicing#2006

Thanks for your review, if possible.