调整INT缓冲区大小；启动扫描后初始化状态为OK

hgdriver/hgdev/hg_scanner.cpp

@@ -733,6 +733,7 @@ void hg_scanner::thread_handle_image_process(void)
 void hg_scanner::working_begin(void*)
 {
 	final_img_index_ = 0;
+	status_ = SCANNER_ERR_OK;
 	notify_ui_working_status(STATU_DESC_SCAN_WORKING, SANE_EVENT_WORKING, SCANNER_ERR_OK);
 	VLOG_MINI_1(LOG_LEVEL_DEBUG_INFO, "[%s] scanning ...\n", hg_log::current_time().c_str());
 }

hgdriver/hgdev/hg_scanner_402.cpp

@@ -1246,7 +1246,7 @@ int hg_scanner_402::read_one_image_from_usb(SANE_Image_Statu statu)
 }
 void hg_scanner_402::discard_all_images(void)
 {
-	char		buf[64];
+	char		buf[32];
 	HGEIntInfo* info = (HGEIntInfo*)buf;
 	int			size = sizeof(buf),
 				oto = 0,