fix verbosity while testing
Call logging.basicConfig otherwise log level is silent during testing
which is inconvenient. Also rename TestWikidata into WikidataHelper so
that pytest does not mistake it for a class that contains tests.
Change-Id: I031d8e14f7706323770057da6bbc2aa8fc02bd26
Signed-off-by: Loic Dachary <loic@dachary.org>