Mismatched nvlist names in zfs_keys_send_space

This causes "zfs send -vt ..." to fail with:

    cannot resume send: Unknown error 1030

It turns out that some of the name/value pairs in the verification
list for zfs_ioc_send_space(), zfs_keys_send_space, had the wrong
name, so the ioctl got kicked out in zfs_check_input_nvpairs().
Update the names accordingly.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: John Poduska <jpoduska@datto.com>
Closes #10978