appvoyer: verbose test execution

With the logs it is impossible to understand why certain commands
fail.

Author: pohly

appveyor.yml

@@ -31,4 +31,5 @@ deploy: false
 
 test_script:
   - go build github.com/golang/dep/cmd/dep
+  - go test ./cmd/dep -args -logs
   - for /f "" %%G in ('go list github.com/golang/dep/...') do ( go test %%G & IF ERRORLEVEL == 1 EXIT 1)