Alias ugettext to gettext method of cwGNUTranslations in Python 3
The former does not exist in Python 3, but we rely on it.
This fixes test_login_bad_password in cubicweb/pyramid/test/test_login.py
which has never passed since being introduced in 6392f34fcdad.
usr/lib/python2*/*-packages/cubicweb/dataimport/
usr/lib/python2*/*-packages/cubicweb/server/
usr/lib/python2*/*-packages/cubicweb/hooks/
usr/lib/python2*/*-packages/cubicweb/sobjects/
usr/lib/python2*/*-packages/cubicweb/schemas/
usr/share/cubicweb/migration/