Specific use case is when utilizing multiple
gcp accounts, the user may provide credentials
for the wrong account.
This change ensures the incorrect credentials
are not cached in auth config, and logs an
appropriate message.
Kubernetes-commit: b92016769e30c541479e81d40dd3584e2f5aa822
Specific use case is GKE users running gcloud/kubectl on Windows
with a cloud sdk installation path containing spaces. Also improving
test coverage using trick borrowed from exec_test.go
Kubernetes-commit: 995ecfe84ea92d77cac2921babbbe03f7c2e4967