zdb -d should accept the numeric objset id

zdb -d should accept the numeric objset id

As an alternative to the dataset name, zdb now allows the decimal
or hexadecimal objset ID to be specified.  When permanent errors
are reported as 2 hexadecimal numbers (objset ID : object ID) in
zpool status; you can now use 'zdb <pool>[/objset ID] object' to
determine the names of the objset and object which have the error.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #9733