In the current world, `zfs diff` will die on certain kinds of errors
that come up on ordinary, not-mangled filesystems - like EINVAL,
which can come from a file with multiple hardlinks having the one
whose name is referenced deleted.
Since it should always be safe to continue, let's relax about all
error codes - still print something for most, but don't immediately
abort when we encounter them.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes#12072