* tests: CoreDNSServerAndPorts
Copy from kubernetes.go and renamed to fit the style, adapted almost
all callers.
This is a mechanicl change, no testdata was changed.
* typos
* cleanup: go vet and golint run
Various cleanups trickered by go vet and golint.
* Fix tests and lowercase all errors
Lowercase all errors, some tests in kubernetes use errors from
kubernetes which do start with a capital letter.