Merge pull request #2033 from ThomasWaldmann/require-succeeding-osx-tests

travis: require succeeding OS X tests, fixes #2028

.travis.yml

@@ -36,8 +36,6 @@ matrix:
           os: osx
           osx_image: xcode6.4
           env: TOXENV=py36
-    allow_failures:
-        - os: osx
 
 install:
     - ./.travis/install.sh