Fixes to teams tests in Django 1.9+

- add edx.org to lms tests KNOWN_HOSTS
- Don't check CourseTeamMembership field mutability on creation

lms/djangoapps/teams/models.py

@@ -182,7 +182,8 @@ class CourseTeamMembership(models.Model):
         """Memberships are immutable, with the exception of last activity
         date.
         """
-        if name in self.immutable_fields:
+        creating_model = name == '_state' or self._state.adding
+        if not creating_model and name in self.immutable_fields:
             # Check the current value -- if it is None, then this
             # model is being created from the database and it's fine
             # to set the value. Otherwise, we're trying to overwrite

lms/envs/test.py

@@ -41,6 +41,7 @@ ALLOWED_HOSTS = [
     '.testserver.fake',
     'test-site.testserver',
     'testserver.fakeother',
+    'edx.org'
 ]
 
 # Silence noisy logs to make troubleshooting easier when tests fail.