plugin/kubernetes: add explicit non-existing ns check (#1350)
plugin/kubernetes: add explicit non-existing ns check (#1350)

We already do the right thing here, but add a test none-the-less.
miekg/coredns,yongtang/coredns,jremond/coredns,chrisohaver/coredns,miekg/coredns,johnbelamaric/coredns,coredns/coredns,ii/coredns,jremond/coredns,johnbelamaric/coredns,ii/coredns