[FIX] product: use product.pricelist in report product_pricelist

We were using hr.contribution.register as a doc_model on the
product.pricelist report which makes no sense since it should show
pricelist informations

addons/product/report/product_pricelist.py

@@ -16,7 +16,7 @@ class report_product_pricelist(models.AbstractModel):
         quantities = self._get_quantity(data)
         docargs = {
             'doc_ids': data.get('ids', data.get('active_ids')),
-            'doc_model': 'hr.contribution.register',
+            'doc_model': 'product.pricelist',
             'docs': products,
             'data': dict(
                 data,