DHCP: Boot reply contains an unknown byte

[simar7]

While testing DHCP boot replies with ServeDHCP(), the responses received contain an unknown byte in the header. See below:

Relevant Test:

func TestServeDHCP(t *testing.T) {
	dhcpServer := newDHCPServer()
	p := dhcp.NewPacket(dhcp.BootReply)

	expected := dhcp.ReplyPacket(p, dhcp.Offer, dhcpServer.ip,
		dhcp.IPAdd(dhcpServer.start, dhcpServer.freeLease()),
		dhcpServer.leaseDuration, dhcpServer.options.SelectOrderOrAll(nil))
	actual := dhcpServer.ServeDHCP(p, dhcp.Discover, nil)

	//TODO: Need a strong assertion
	assert.ObjectsAreEqual(actual, expected)
}

Output:

			Diff:
			--- Expected
			+++ Actual
			@@ -2,3 +2,3 @@
			  00000000  02 01 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
			- 00000010  ac 0a 00 27 00 00 00 00  00 00 00 00 00 00 00 00  |...'............|
			+ 00000010  ac 0a 00 31 00 00 00 00  00 00 00 00 00 00 00 00  |...1............|
			  00000020  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|