Exclude sqlite from Travis builds. There's a Django bug that breaks sqlite (https://code.djangoproject.com/ticket/30754#ticket) and I don't want all builds to fail (and potentially mask other issues) until the upstream bugfix is released.

.travis.yml

@@ -8,7 +8,7 @@ install:
     - pip install -r requirements.txt
     - pip install braintree coveralls mock mysqlclient reportlab apprise
 env:
-  - DB=sqlite
+  # - DB=sqlite
   - DB=mysql
   - DB=postgres
 services: