Allow kube-dns to load its configuration from a config map

- Adds command line flags --config-map, --config-map-ns.
- Fixes 36194 (https://github.com/kubernetes/kubernetes/issues/36194)
- Update kube-dns yamls
- Update bazel (hack/update-bazel.sh)
- Update known command line flags
- Temporarily reference new kube-dns image (this will be fixed with
  a separate commit when the DNS image is created)

pkg/dns/config/config_test.go

@@ -0,0 +1,55 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package config
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestValidate(t *testing.T) {
+	for _, testCase := range []struct {
+		config   *Config
+		hasError bool
+	}{
+		{
+			config: &Config{Federations: map[string]string{}},
+		},
+		{
+			config: &Config{
+				Federations: map[string]string{
+					"abc": "d.e.f",
+				},
+			},
+		},
+		{
+			config: &Config{
+				Federations: map[string]string{
+					"a.b": "cdef",
+				},
+			},
+			hasError: true,
+		},
+	} {
+		err := testCase.config.Validate()
+		if !testCase.hasError {
+			assert.Nil(t, err, "should be valid", testCase)
+		} else {
+			assert.NotNil(t, err, "should not be valid", testCase)
+		}
+	}
+}