fix(config): Remove autocommit option from DB config (#195)

Django 1.7 already defaults to `True` for this and in Django 1.8, which
is what the latest Sentry uses, the option is removed and causes a DB
connection error so dropping it to fix git builds.

sentry.conf.py

@@ -83,9 +83,6 @@ if postgres:
                 env('SENTRY_POSTGRES_PORT')
                 or ''
             ),
-            'OPTIONS': {
-                'autocommit': True,
-            },
         },
     }