Create a CI Smoke test for CoreDNS

[denverwilliams]

Looks like there are some existing CoreDNS tests against a k8s cluster that we can use.
https://github.com/coredns/coredns/blob/master/test/kubernetes_test.go

[denverwilliams]

Setup for Development and Testing for CoreDNS
https://github.com/coredns/coredns/blob/master/middleware/kubernetes/DEV-README.md

Going to implement for a Smoke Test against CI Build

[denverwilliams]

Smoke Tests for CoreDNS are Working

bash-4.3# cd $GOPATH/src/github.com/coredns/coredns/test
bash-4.3# go test -v -tags k8s
=== RUN   TestAuto
=== RUN   TestAutoNonExistentZone
=== RUN   TestAutoAXFR
=== RUN   TestLookupCache
=== RUN   TestChaos
--- PASS: TestChaos (0.00s)
=== RUN   TestLookupDS
=== RUN   TestZoneExternalCNAMELookupWithoutProxy
=== RUN   TestZoneExternalCNAMELookupWithProxy
=== RUN   TestZoneReload
=== RUN   TestZoneSRVAdditional
=== RUN   TestTempFile
=== RUN   TestGrpc
--- PASS: TestGrpc (0.00s)
=== RUN   TestKubernetesIntegration
--- PASS: TestKubernetesIntegration (1.01s)
=== RUN   TestKubernetesIntegrationPodsInsecure
--- PASS: TestKubernetesIntegrationPodsInsecure (1.00s)
=== RUN   TestKubernetesIntegrationPodsVerified
--- PASS: TestKubernetesIntegrationPodsVerified (1.00s)
=== RUN   TestKubernetesIntegrationCidrReverseZone
--- PASS: TestKubernetesIntegrationCidrReverseZone (1.00s)
=== RUN   TestKubernetesIntegrationPartialCidrReverseZone
--- PASS: TestKubernetesIntegrationPartialCidrReverseZone (1.00s)
=== RUN   TestKubernetesIntegrationAllNSExposed
--- PASS: TestKubernetesIntegrationAllNSExposed (1.00s)
=== RUN   TestKubernetesIntegrationFallthrough
--- PASS: TestKubernetesIntegrationFallthrough (1.01s)
=== RUN   TestMetricsServer
--- PASS: TestMetricsServer (0.03s)
=== RUN   TestMetricsRefused
--- PASS: TestMetricsRefused (0.00s)
=== RUN   TestMetricsAuto
--- PASS: TestMetricsAuto (2.20s)
=== RUN   TestLookupBalanceRewriteCacheDnssec
=== RUN   TestProxyErratic
--- PASS: TestProxyErratic (5.00s)
=== RUN   TestProxyWithHTTPCheckOK
--- PASS: TestProxyWithHTTPCheckOK (0.00s)
=== RUN   TestLookupProxy
=== RUN   TestLookupDnsWithForcedTcp
=== RUN   TestReload
--- PASS: TestReload (0.00s)
=== RUN   TestReverseFallthrough
=== RUN   TestRewrite
=== RUN   TestProxyToChaosServer
=== RUN   TestLookupWildcard
--- PASS: TestTempFile (0.00s)
--- PASS: TestLookupProxy (0.00s)
--- PASS: TestLookupDnsWithForcedTcp (0.00s)
--- PASS: TestRewrite (0.00s)
--- PASS: TestLookupWildcard (0.00s)
--- PASS: TestZoneSRVAdditional (0.00s)
--- PASS: TestZoneExternalCNAMELookupWithoutProxy (0.00s)
--- PASS: TestProxyToChaosServer (0.01s)
--- PASS: TestReverseFallthrough (0.01s)
--- PASS: TestLookupBalanceRewriteCacheDnssec (0.01s)
--- PASS: TestZoneExternalCNAMELookupWithProxy (0.01s)
--- PASS: TestLookupDS (0.00s)
--- PASS: TestAutoNonExistentZone (0.00s)
--- PASS: TestZoneReload (1.01s)
--- PASS: TestAutoAXFR (1.10s)
--- PASS: TestLookupCache (2.00s)
--- PASS: TestAuto (2.20s)
PASS
ok  	github.com/coredns/coredns/test	16.544s

[hh]

Let's get this into the pipeline today.