Cleanup appveyor config

Author: sdispater

appveyor.yml

@@ -21,14 +21,12 @@ install:
   # Create poetry virtualenv
   - pip install virtualenv
   - virtualenv --python="C:/Python36-x64\\python.exe" "venv-poetry"
-  - "python -c \"import sys; print(sys.executable)\""
   - venv-poetry\\Scripts\\pip.exe install poetry --pre
 
   # Create current python virtualenv
   - python -m virtualenv venv
   - venv\Scripts\activate.bat
-  - "SET VIRTUAL_ENV=venv"
-  - "python -c \"import sys; print(sys.executable)\""
+  - "SET VIRTUAL_ENV=venv"  # Seems that activate.bat does not set VIRTUAL_ENV
 
   # Install dependencies
   - pip install codecov