Remove python 2.7 reference from appveyor now that the py27 env is gone

appveyor.yml

@@ -4,9 +4,6 @@ cache:
   - 'C:\\tmp'
 environment:
   matrix:
-    - PYTHON: "C:\\Python27"
-      TOXENV: "py27"
-
     - PYTHON: "C:\\Python34"
       TOXENV: "py34"