also str representation of unicode character is different.

 - the test was using wrong attribute and it was using DummyLocalizer,
which breaks the site configuration. Fix the test and use mock
 - fix ods style not to translate untranslatable columns

Page templates have a builtin translation system (with i18n:) and an
"unicode conflict resolver", so it was not necessary to explicitly
convert to unicode on python2 and this simplifies the transition to
python3