Update iptable.Exists API in integration-cli

Signed-off-by: Arko Dasgupta <arko.dasgupta@docker.com>

integration-cli/docker_cli_daemon_test.go

@@ -945,12 +945,13 @@ func (s *DockerDaemonSuite) TestDaemonLinksIpTablesRulesWhenLinkAndUnlink(c *tes
 
 	sourceRule := []string{"-i", bridgeName, "-o", bridgeName, "-p", "tcp", "-s", childIP, "--sport", "80", "-d", parentIP, "-j", "ACCEPT"}
 	destinationRule := []string{"-i", bridgeName, "-o", bridgeName, "-p", "tcp", "-s", parentIP, "--dport", "80", "-d", childIP, "-j", "ACCEPT"}
-	if !iptables.Exists("filter", "DOCKER", sourceRule...) || !iptables.Exists("filter", "DOCKER", destinationRule...) {
+	iptable := iptables.GetIptable(iptables.IPv4)
+	if !iptable.Exists("filter", "DOCKER", sourceRule...) || !iptable.Exists("filter", "DOCKER", destinationRule...) {
 		c.Fatal("Iptables rules not found")
 	}
 
 	s.d.Cmd("rm", "--link", "parent/http")
-	if iptables.Exists("filter", "DOCKER", sourceRule...) || iptables.Exists("filter", "DOCKER", destinationRule...) {
+	if iptable.Exists("filter", "DOCKER", sourceRule...) || iptable.Exists("filter", "DOCKER", destinationRule...) {
 		c.Fatal("Iptables rules should be removed when unlink")
 	}