Also tweak `pathAccessible` to ignore other relevant errors too. It was
documented as ignoring permission errors but it was only ignoring
`EPERM`, which comes from the darwin sandbox, and not ignoring `EACCESS`
which is the real permission error. I figured it also makes sense to
ignore `ELOOP`.
Fixes: #560
Change-Id: Ibb849b68d07386eb80afb52b57f7d12b3a48a202
