Fix SIGSEGV in xmpp_component (#126)

* SIGSEGV in xmpp_component example with Prosody #126

component.go

@@ -7,9 +7,8 @@ import (
 	"encoding/xml"
 	"errors"
 	"fmt"
-	"io"
-
 	"gosrc.io/xmpp/stanza"
+	"io"
 )
 
 type ComponentOptions struct {
@@ -50,7 +49,6 @@ type Component struct {
 
 	// read / write
 	socketProxy io.ReadWriter // TODO
-	decoder     *xml.Decoder
 }
 
 func NewComponent(opts ComponentOptions, r *Router) (*Component, error) {
@@ -90,7 +88,7 @@ func (c *Component) Resume(sm SMState) error {
 	}
 
 	// Check server response for authentication
-	val, err := stanza.NextPacket(c.decoder)
+	val, err := stanza.NextPacket(c.transport.GetDecoder())
 	if err != nil {
 		c.updateState(StatePermanentError)
 		return NewConnError(err, true)
@@ -125,7 +123,7 @@ func (c *Component) SetHandler(handler EventHandler) {
 // Receiver Go routine receiver
 func (c *Component) recv() (err error) {
 	for {
-		val, err := stanza.NextPacket(c.decoder)
+		val, err := stanza.NextPacket(c.transport.GetDecoder())
 		if err != nil {
 			c.updateState(StateDisconnected)
 			return err