Run import-order only in py3.5 in Travis

Author: dittos

.travis.yml

@@ -7,12 +7,15 @@ python:
 - 3.5
 - pypy
 install:
-- pip install pytest-cov coveralls flake8
+- pip install pytest-cov coveralls flake8 import-order
 - pip install pytest>=2.7.3 --upgrade
 - pip install -e .
 script:
 - flake8
-- import-order graphql
 - py.test --cov=graphql tests
 after_success:
 - coveralls
+matrix:
+  include:
+    - python: "3.5"
+      script: import-order graphql