Attachments with `path` are stored as `resources/sha1.ext` zip entries
and extracted under `report-dir/tmp` when merging. This way normal
fs.readFile keeps working as before even thought the file path is
different. The clients should rely on `attachment.name` instead of
`attachment.path` when deriving user visible titles in the UI. If this
turns out not to be the case we can reconsider later.
#10437
