Fix non-PR AppVeyor behaviour
Fix non-PR AppVeyor behaviour

(It's hard to get test coverage without actually running the tests.)

iantalarico/google-cloud-dotnet,evildour/google-cloud-dotnet,jskeet/google-cloud-dotnet,jskeet/google-cloud-dotnet,jskeet/google-cloud-dotnet,jskeet/google-cloud-dotnet,googleapis/google-cloud-dotnet,evildour/google-cloud-dotnet,evildour/google-cloud-dotnet,iantalarico/google-cloud-dotnet,iantalarico/google-cloud-dotnet,jskeet/gcloud-dotnet,googleapis/google-cloud-dotnet,googleapis/google-cloud-dotnet,jskeet/google-cloud-dotnet