Merge pull request #602 from davecheney/fix-appveyor-build-breakage

appveyor.yml: fix failure to detect windows build errors

Author: sdboyer

appveyor.yml

@@ -34,4 +34,4 @@ deploy: false
 
 test_script:
   - go build github.com/golang/dep/cmd/dep
-  - for /f "" %%G in ('go list github.com/golang/dep/... ^| find /i /v "/vendor/"') do @go test %%G
+  - for /f "" %%G in ('go list github.com/golang/dep/... ^| find /i /v "/vendor/"') do ( go test %%G & IF ERRORLEVEL == 1 EXIT 1)