Fix failing fuse TestReaddirWalk test

Fix failing tests

```
=== RUN TestReaddirWalk
--- FAIL: TestReaddirWalk (0.00 seconds)
        all_test.go:448: Walk got:
                dirwalk = drwxr-xr-x
                dirwalk/1.txt = -rw-r--r-- (size 3)
                dirwalk/sub = drwxr-xr-x
                dirwalk/sub/2.txt = -rw-r--r-- (size 7)
                Want:
                dirwalk = drwxr-x---
                dirwalk/1.txt = -rw-r----- (size 3)
                dirwalk/sub = drwxr-x---
                dirwalk/sub/2.txt = -rw-r----- (size 7)
```