Fix GPIO service and cleanup response handling

src/plugins/AdminPlugin.h

@@ -6,8 +6,6 @@
  */
 class AdminPlugin : public ProtobufPlugin<AdminMessage>
 {
-  MeshPacket *reply = NULL;
-  
   public:
     /** Constructor
      * name is for debugging output
@@ -21,10 +19,6 @@ class AdminPlugin : public ProtobufPlugin<AdminMessage>
     */
     virtual bool handleReceivedProtobuf(const MeshPacket &mp, const AdminMessage *p);
 
-    /** Messages can be received that have the want_response bit set.  If set, this callback will be invoked
-     * so that subclasses can (optionally) send a response back to the original sender.  */
-    virtual MeshPacket *allocReply();
-
   private:
     void handleSetOwner(const User &o);
     void handleSetChannel(const Channel &cc);