enable usb debug only with release builds

include/config.h

 #define MENU_PREFER_VOLCANO
 //#define MENU_PREFER_CRAFTY
 
+#ifdef NDEBUG
+// Release build
 #define AUTO_MOUNT_MASS_STORAGE
 #define AUTO_LOG_ON_MASS_STORAGE
+#define DEBUG_DISK_WRITE_SOURCES
+#endif
 
 #define WATCHDOG_PERIOD_MS 1000
 
 
 #define SERIAL_WRITES_BLOCK_WHEN_BUFFER_FULL
 
-#define DEBUG_DISK_WRITE_SOURCES
-
 #define DISK_BLOCK_SIZE 512
 
 #ifdef DEBUG_DISK_WRITE_SOURCES