[FIX] rma: do not force reservation on supplier RMA deliveries

* remove code call to unexisting `force_asign`.
* only one model per model file and rename as appropriate.

rma/models/stock_rule.py

@@ -0,0 +1,41 @@
+# Copyright (C) 2017-22 ForgeFlow S.L.
+# License LGPL-3.0 or later (https://www.gnu.org/licenses/lgpl.html)
+
+from odoo import models
+
+
+class StockRule(models.Model):
+    _inherit = "stock.rule"
+
+    def _get_stock_move_values(
+        self,
+        product_id,
+        product_qty,
+        product_uom,
+        location_id,
+        name,
+        origin,
+        company_id,
+        values,
+    ):
+        res = super()._get_stock_move_values(
+            product_id,
+            product_qty,
+            product_uom,
+            location_id,
+            name,
+            origin,
+            company_id,
+            values,
+        )
+        if "rma_line_id" in values:
+            line = values.get("rma_line_id")
+            res["rma_line_id"] = line.id
+            if line.delivery_address_id:
+                res["partner_id"] = line.delivery_address_id.id
+            else:
+                res["partner_id"] = line.rma_id.partner_id.id
+            dest_loc = self.env["stock.location"].browse([res["location_dest_id"]])[0]
+            if dest_loc.usage == "internal":
+                res["price_unit"] = line.price_unit
+        return res