Don't deepcopy objects before mask_dict_password
Don't deepcopy objects before mask_dict_password

As far as I can tell, mask_dict_password does not modify the object
passed in to it[0]. As such, this deepcopy only adds an unnecessary
requirement on the policy objects that makes it possible for a call
to fail in a different way when debug logging is enabled. Since this
is pretty terrible, let's get rid of it.

Change-Id: I34eace9806e6ed7c9c6206a34f55debc0c20bac6
Closes-Bug: 1886984
0: https://github.com/openstack/oslo.utils/blob/4fe75b7e1bd3144282f107ce7cb61880257c7c1e/oslo_utils/strutils.py#L349

openstack/oslo.policy