Revert "Keep the original OPT record before setting the payload size"

This reverts commit d49a7b462d.

dnscrypt-proxy/plugin_get_set_payload_size.go

@@ -35,6 +35,13 @@ func (plugin *PluginGetSetPayloadSize) Eval(pluginsState *PluginsState, msg *dns
 	pluginsState.dnssec = dnssec
 	pluginsState.maxPayloadSize = Min(MaxDNSUDPPacketSize-ResponseOverhead, Max(pluginsState.originalMaxPayloadSize, pluginsState.maxPayloadSize))
 	if pluginsState.maxPayloadSize > 512 {
+		extra2 := []dns.RR{}
+		for _, extra := range msg.Extra {
+			if extra.Header().Rrtype != dns.TypeOPT {
+				extra2 = append(extra2, extra)
+			}
+		}
+		msg.Extra = extra2
 		msg.SetEdns0(uint16(pluginsState.maxPayloadSize), dnssec)
 	}
 	return nil