Commit df583073 introduced the ability to list the snapshots for a
specified dataset. This change inadvertently resulted in only the top-
level snapshots being listed when no dataset was specified. Fix this
issue by adding an additional check to determine if a dataset was
provided to avoid incorrectly restricting the depth.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed-by: Alek Pinchuk <apinchuk@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8591Closes#8594