Remove unnecessary "sudo" from travis config

Author: srittau

.travis.yml

@@ -10,21 +10,15 @@ jobs:
     - stage: test
       python: 2.7
       dist: trusty
-      sudo: false
     - stage: test
       python: 3.4
       dist: trusty
-      sudo: false
     - stage: test
       python: 3.5
       dist: trusty
-      sudo: false
     - stage: test
       python: 3.6
       dist: trusty
-      sudo: false
     - stage: test
       python: 3.7
       dist: xenial
-      sudo: true
-