Fix incremental recursive encrypted receive

Fix incremental recursive encrypted receive

Currently, incremental recursive encrypted receives fail to work
for any snapshot after the first. The reason for this is because
the check in zfs_setup_cmdline_props() did not properly realize
that when the user attempts to use '-x encryption' in this
situation, they are not really overriding the existing encryption
property and instead are attempting to prevent it from changing.
This resulted in an error message stating: "encryption property
'encryption' cannot be set or excluded for raw or incremental
streams".

This problem is fixed by updating the logic to expect this use
case.

Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #9494