Do not copy warnings nor applications when copying user

There are record rules on the targets which prevent to copy users.
Also it is not expected to copy those fields when copying users.

issue6049

trytond/res/user.py

@@ -309,6 +309,8 @@ class User(ModelSQL, ModelView):
         default = default.copy()
 
         default['password'] = ''
+        default.setdefault('warnings')
+        default.setdefault('applications')
 
         new_users = []
         for user in users: