Revert "[IMPROV] Reduce usage of unicode()"

The change completely breaks:
https://travis-ci.org/wikimedia/pywikibot-core/builds/43211148

This reverts commit 58fd995ac73efa1c7807c0315c8c2140eb22011b.

Change-Id: I815faa4f75c2a473dfa444da9248607717e5288a