Before this change, rclone would return an error from the listing if
there was an unreadable directory, or if there was a problem stat-ing
a directory entry. This was frustrating because the command
completely aborts at that point when there is work it could do.
After this change rclone lists the directories and reports ERRORs for
unreadable directories or problems stat-ing files, but does return an
error from the listing. It does set the error flag which means the
command will fail (and objects won't be deleted with `rclone sync`).
This brings rclone's behaviour exactly in to line with rsync's
behaviour. It does as much as possible, but doesn't let the errors
pass silently.
Fixes#3179
9c6f3ae82c