Fix import of social_core.exceptions in sso/pipeline.py

Signed-off-by: Joachim Jablon <ewjoachim@gmail.com>

awx/sso/pipeline.py

@@ -5,7 +5,7 @@
 import re
 
 # Python Social Auth
-from social.exceptions import AuthException
+from social_core.exceptions import AuthException
 
 # Django
 from django.utils.translation import ugettext_lazy as _

awx/sso/tests/unit/test_pipeline.py

@@ -0,0 +1,2 @@
+def test_module_loads():
+    from awx.sso import pipeline  # noqa