Add parsing of the rewind options.
When I was upstreaming the change [1], I omitted the part where we
detect that the pool should be rewind. When the FreeBSD repo has
synced with the OpenZFS, this part of the code was removed.
[1] FreeBSD repo: 277f38abff
[2] OpenZFS repo: f2c027bd6a
Originally reviewed by: tsoome, allanjude
Originally reviewed by: kevans (ok from high-level overview)
Signed-off-by: Mariusz Zaborski <oshogbo@vexillium.org>
PR: 254152
Reported by: Zhenlei Huang <zlei.huang at gmail.com>
Obtained from: https://github.com/openzfs/zfs/pull/11730