Fix zfs incremental send remove '-o' properties

When receiving an incremental send stream with intermediary snapshots
zfs_receive_one() does not correctly identify the top-level dataset:
consequently we restore said snapshots as if they were children
datasets in the hierarchy, forcing inheritance of any property received
with 'zfs send -o' and effectively removing any locally set value.

The test case did not correctly verify this situation because it uses
adjacent snapshots, basically testing 'zfs send -i' instead of
'zfs send -I': this commit adds an additional intermediary snapshot to
the test script.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #7478