[connection] remove ensure_cnx_set context manager uses
It has been deprecated in a previous changeset and is now a no-op.
Related to #2919309.
# -*- coding: utf-8 -*-
# copyright %(year)s %(author)s, all rights reserved.
# contact %(author-web-site)s -- mailto:%(author-email)s
#
%(long-license)s
"""%(distname)s views/forms/actions/components for web ui"""