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
External-issue: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254152
Originally reviewed by: tsoome, allanjude
Originally reviewed by: kevans (ok from high-level overview)
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mariusz Zaborski <oshogbo@vexillium.org>
Closes#11730
e464f7c7cc