Fix bad Django test suite interaction with get_client default.

authenticated_api_view and authenticated_json_view call
update_user_activity with a client generated using
@has_request_variables with a default of e.g. get_client("website").
Because that get_client call only happens once on importing the
module, if those client objects didn't exist previously in the
fixtures, then the first test will generate objects with ids 2 and 3,
and then the second test will dump the database, restore from the
fixtures, and then eventually generate client objects with ids 4 and
5.  But since the default values were only computed at module load,
we'll still end calling add_user_activity with client objects with ids
2 and 3, which don't exist in the newly restored database.

Fix this madness by just making sure those two client objects exist in
the database.

(imported from commit d940e129d077a560d9a0f96ec3daa2e16ce21c8b)

zephyr/management/commands/populate_db.py

@@ -208,6 +208,12 @@ class Command(BaseCommand):
                 ]
             create_users(realms, internal_humbug_users_nosubs)
 
+            # Create the "website" and "API" clients; if we don't, the
+            # default values in zephyr/decorators.py will not work
+            # with the Django test suite.
+            get_client("website")
+            get_client("API")
+
             self.stdout.write("Successfully populated test database.\n")
         if options["replay_old_messages"]:
             restore_saved_messages()