fix #4448 (by seeing there is actually no problem) (#4517)

Print directory names when listing directories

src/FSCommon.cpp

@@ -249,6 +249,7 @@ void listDir(const char *dirname, uint8_t levels, bool del)
                     file.close();
                 }
 #else
+                LOG_DEBUG(" %s (directory)\n", file.name());
                 listDir(file.name(), levels - 1, del);
                 file.close();
 #endif