It's the main recommendation to set xattr=sa
even in man pages, so let's set it by default.
xattr=sa don't use feature flag, so in the worst
case we'll have non-readable xattrs by other
non-openzfs platforms.
Non-overridden default `xattr` prop of existing pools
will automatically use `sa` after this commit too.
Signed-off-by: George Melikov <mail@gmelikov.ru>
c49fa3e0bd