Python-modernize on edx-platform (350 of 380)

After executing python-modernize and isort, few changes
occurred in import sequence as well as unicode func is
replaced by six.text_type func.

INCR-453

lms/djangoapps/badges/handlers.py

@@ -1,6 +1,8 @@
 """
 Badges related signal handlers.
 """
+from __future__ import absolute_import
+
 from django.dispatch import receiver
 
 from lms.djangoapps.badges.events.course_meta import award_enrollment_badge

lms/djangoapps/email_marketing/models.py

@@ -1,6 +1,8 @@
 """
 Email-marketing-related models.
 """
+from __future__ import absolute_import
+
 from config_models.models import ConfigurationModel
 from django.db import models
 from django.utils.translation import ugettext_lazy as _