ext2: Allow to open `root' as a subdirectory

This is useful to follow `..' directory entries.
diff --git a/src/filo-fs-ext2.adb b/src/filo-fs-ext2.adb
index 51f872b..1850b50 100644
--- a/src/filo-fs-ext2.adb
+++ b/src/filo-fs-ext2.adb
@@ -844,7 +844,7 @@
 
             -- Only check filenames of exact same length
             Inode := Inode_0_Index (Read_LE32 (Dir_Entry_Header, 0));
-            if Inode > Root_Inode and then
+            if Inode >= Root_Inode and then
                File_Name'Length = Natural (Dir_Entry_Header (6))
             then
                pragma Warnings