[test/web] fix invisibly bogus test (prepares #2755994) The test was wrong but that was cancelled out by a cache effect and fuzzy naming. Wiping the entity caches restores sanity: the choices list are the same before and after the SET. Also field.choices uses entity.unrelated but always returns related + unrelated elements. Hence `choice` replaces `unrelated` where it makes sense. AssertIn is used in place of AssertTrue.

# -*- 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 postcreate script, executed at instance creation time or when
the cube is added to an existing instance.

You could setup site properties or a workflow here for example.
"""

# Example of site property change
#set_property('ui.site-title', "<sitename>")