Fix duplicate AppVeyor key

Author: STRML

appveyor.yml

@@ -5,22 +5,16 @@ environment:
     - node_version: "7"
     - node_version: "6"
     - node_version: "4"
+  IE_BIN: "%PROGRAMFILES%\\Internet Explorer\\iexplorer.exe"
 
 cache:
-  - node_modules
-
-environment:
-  IE_BIN: "%PROGRAMFILES%\\Internet Explorer\\iexplorer.exe"
+  - "%LOCALAPPDATA%/Yarn"
 
 install:
-  - ps: Install-Product node $env:node_version
   - choco install -i yarn
   - refreshenv
   - yarn install
 
-cache:
- - "%LOCALAPPDATA%/Yarn"
-
 test_script:
   - npm run test-ie