Simplified default_connection check

If I understand this correctly, these lines are supposed to add a static path to `urlpatterns` unless an amazonaws connection exists. I do the same with a `getatr` to remove the need for a try/catch block and second assignment (even though only one assignment is reached, of course). I also used `!=` to make the if block a little more useful. 

Sorry about going past 79 characters. I wasn't sure how you preferred to wrap if clauses and everything I came up with looked ugly.