Make `zpool clear` to reopen also reconnected cache and spare devices.
This issue was found by FreeBSD developer Alexander Motin <mav@FreeBSD.org>. The change was committed as FreeBSD r253991 ( http://svnweb.freebsd.org/changeset/base/253991 ), the commit message on FreeBSD was:
Make `zpool clear` to reopen also reconnected cache and spare devices. Since `zpool status` reports about such kinds of errors, it is strange that they are not cleared by `zpool clear`.