Updated appvayor file again

appveyor.yml

@@ -8,7 +8,8 @@ environment:
   GOPATH: c:\gopath
 
 install:
-  - choco install mingw
+  - choco install -y mingw
+  - set PATH=C:\tools\mingw64\bin;%PATH%
   - echo %PATH%
   - echo %GOPATH%
   - go version