ran python-modernize and isort on files mentioned in INCR-367

changes made to comply with pylint

openedx/core/djangoapps/credentials/admin.py

@@ -2,6 +2,8 @@
 Django admin pages for credentials support models.
 """
 
+from __future__ import absolute_import
+
 from config_models.admin import ConfigurationModelAdmin
 from django.contrib import admin