debugfs: fix rdump so it can start from the root directory

Previously "rdump / /tmp/out" would fail with the error message:

rdump: File exists while making directory /tmp/out/

Also fix the fast symlink detection logic so that it works when a
symlink has one or more extended attributes.

Addresses-Debian-Bug: #766125

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
1 file changed