Make StorageClient.Service throw NotImplementedException
Make StorageClient.Service throw NotImplementedException

This will only be a visible change for users who subclass/fake StorageClient.

This fixes issue #126.

iantalarico/google-cloud-dotnet,chrisdunelm/google-cloud-dotnet,chrisdunelm/gcloud-dotnet,evildour/google-cloud-dotnet,jskeet/google-cloud-dotnet,googleapis/google-cloud-dotnet,jskeet/google-cloud-dotnet,ctaggart/google-cloud-dotnet,googleapis/google-cloud-dotnet,benwulfe/google-cloud-dotnet,ctaggart/google-cloud-dotnet,evildour/google-cloud-dotnet,iantalarico/google-cloud-dotnet,chrisdunelm/google-cloud-dotnet,iantalarico/google-cloud-dotnet,jskeet/google-cloud-dotnet,jskeet/google-cloud-dotnet,evildour/google-cloud-dotnet,jskeet/google-cloud-dotnet,chrisdunelm/google-cloud-dotnet,benwulfe/google-cloud-dotnet,benwulfe/google-cloud-dotnet,jskeet/gcloud-dotnet,googleapis/google-cloud-dotnet,ctaggart/google-cloud-dotnet