[pricelist] fix bug set no volumes are set

flaschengeist/plugins/pricelist/pricelist_controller.py

@@ -188,7 +188,8 @@ def update_drink(identifier, data):
         if drink_type:
             drink.type = drink_type
         if volumes is not None and session.user_.has_permission(EDIT_VOLUME):
-            set_volumes(volumes, drink)
+            drink.volumes = []
+            drink.volumes = set_volumes(volumes)
         if len(tags) > 0:
             drink.tags = tags
         db.session.commit()
@@ -197,11 +198,13 @@ def update_drink(identifier, data):
         raise BadRequest
 
 
-def set_volumes(volumes, drink):
+def set_volumes(volumes):
+    retVal = []
     if not isinstance(volumes, list):
         raise BadRequest
     for volume in volumes:
-        drink.volumes.append(set_volume(volume))
+        retVal.append(set_volume(volume))
+    return retVal
 
 
 def delete_drink(identifier):