Move the kubelet network package down to dockershim

With CRI, kubelet no longer sets up networking for the pods. The
dockershim package is the rightful owner and the only user of the
newtork package. This change moves the package into dockershim to make
the distinction obvious, and untangles the codebase.

The`network/dns`is kept in the original package since it is only used by
kubelet.

pkg/kubelet/kubelet_network_test.go

@@ -22,97 +22,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestNodeIPParam(t *testing.T) {
-	type test struct {
-		nodeIP   string
-		success  bool
-		testName string
-	}
-	tests := []test{
-		{
-			nodeIP:   "",
-			success:  false,
-			testName: "IP not set",
-		},
-		{
-			nodeIP:   "127.0.0.1",
-			success:  false,
-			testName: "IPv4 loopback address",
-		},
-		{
-			nodeIP:   "::1",
-			success:  false,
-			testName: "IPv6 loopback address",
-		},
-		{
-			nodeIP:   "224.0.0.1",
-			success:  false,
-			testName: "multicast IPv4 address",
-		},
-		{
-			nodeIP:   "ff00::1",
-			success:  false,
-			testName: "multicast IPv6 address",
-		},
-		{
-			nodeIP:   "169.254.0.1",
-			success:  false,
-			testName: "IPv4 link-local unicast address",
-		},
-		{
-			nodeIP:   "fe80::0202:b3ff:fe1e:8329",
-			success:  false,
-			testName: "IPv6 link-local unicast address",
-		},
-		{
-			nodeIP:   "0.0.0.0",
-			success:  false,
-			testName: "Unspecified IPv4 address",
-		},
-		{
-			nodeIP:   "::",
-			success:  false,
-			testName: "Unspecified IPv6 address",
-		},
-		{
-			nodeIP:   "1.2.3.4",
-			success:  false,
-			testName: "IPv4 address that doesn't belong to host",
-		},
-	}
-	addrs, err := net.InterfaceAddrs()
-	if err != nil {
-		assert.Error(t, err, fmt.Sprintf(
-			"Unable to obtain a list of the node's unicast interface addresses."))
-	}
-	for _, addr := range addrs {
-		var ip net.IP
-		switch v := addr.(type) {
-		case *net.IPNet:
-			ip = v.IP
-		case *net.IPAddr:
-			ip = v.IP
-		}
-		if ip.IsLoopback() || ip.IsLinkLocalUnicast() {
-			break
-		}
-		successTest := test{
-			nodeIP:   ip.String(),
-			success:  true,
-			testName: fmt.Sprintf("Success test case for address %s", ip.String()),
-		}
-		tests = append(tests, successTest)
-	}
-	for _, test := range tests {
-		err := validateNodeIP(net.ParseIP(test.nodeIP))
-		if test.success {
-			assert.NoError(t, err, "test %s", test.testName)
-		} else {
-			assert.Error(t, err, fmt.Sprintf("test %s", test.testName))
-		}
-	}
-}
-
 func TestGetIPTablesMark(t *testing.T) {
 	tests := []struct {
 		bit    int