Fix case where we have a read cap to a dir, and a descendant write cap to the target was revoked.
Fix case where we have a read cap to a dir,
and a descendant write cap to the target was revoked.

This was also found by the fuzzer.

Peergos/Peergos,Peergos/Peergos,ianopolous/Peergos,Peergos/Peergos,ianopolous/Peergos,ianopolous/Peergos