BUG: with "rootfull" you can't run: "error: FileNotFound"

**How to reproduce:**

```
$ dockerc_x86-64 -i docker://hello-world:linux -o hello-world.x86-64
$ dockerc_x86-64 -i docker://hello-world:linux -o hello-world-root.x86-64 --rootfull

$ ./hello-world.x86-64  -> OK

$ sudo ./hello-world-root.x86-64  -> ERROR
error: FileNotFound
```

I'm not sure if this is an ancient bug, but the current version has it.

Please, fix it!
