Prevent o2m-records to be deleted on client-side

When I delete some records of an one2many-field in an on-change-Event, the
deleted records are sent to the client and the client hides them in the list.
Pressing the save button the record loads again including the deleted o2m-records.

The reason is the force_remove-flag. This will delete the record on the
client-side and therefore this change will not be reflected on the server side.

issue3091
review744002
(transplanted from e40190b28b312f3dd63bceb167698a885826ea0e)

tryton/gui/window/view_form/model/field.py

@@ -699,7 +699,7 @@ class O2MField(CharField):
                     to_remove.append(record2)
         for record2 in to_remove:
             record.value[self.name].remove(record2, signal=False,
-                force_remove=True)
+                force_remove=False)
 
         if value and (value.get('add') or value.get('update', [])):
             record.value[self.name].add_fields(fields, signal=False)