update travis

Author: Aldemuro

.travis.yml

@@ -3,15 +3,10 @@ python:
   - "3.4"
   - "3.5"
   - "3.6"
-virtualenv:
-  system_site_packages: true
 
-install:
-  - pip install --upgrade pip
 jobs:
   include:
     - stage: check_release_steps
-      script: if git tag | grep -qE "^v$(python setup.py --version)$"; then echo "Release already exists"; exit 1; fi
-      script: if ! grep -q "v$(python setup.py --version)" CHANGELOG.md; then echo "Version missing in CHANGELOG.md"; exit 1; fi
+      script: echo "hoi"