Update Travis config to make tests pass with xenial

Author: yceruto

.travis.yml

@@ -1,14 +1,11 @@
+sudo: required
+dist: xenial
 language: python
 
 python:
   - 3.5
   - 3.6
-
-matrix:
-  include:
-    - python: 3.7
-      dist: xenial
-      sudo: true
+  - 3.7
 
 env:
   - DJANGO_VERSION=2.*

django_ajax/mixin.py

@@ -22,5 +22,4 @@ def dispatch(self, request, *args, **kwargs):
         if self.json_encoder:
             ajax_kwargs['cls'] = self.json_encoder
 
-        return ajax(**ajax_kwargs)(super(
-            AJAXMixin, self).dispatch)(request, *args, **kwargs)
+        return ajax(**ajax_kwargs)(super(AJAXMixin, self).dispatch)(request, *args, **kwargs)