streams_depot: Simplify stream_dir()

streams_depot: Simplify stream_dir()

The only place where we could have entered the mark_valid() code path
is via openat(). In openat(":stream") with O_CREAT fsp->base_fsp() is
fully opened from within create_file_unixpath(). Change
streams_depot_openat() to call the FSETXATTR from mark_file_valid()
directly. This means we don't need the expensive synthetic_pathref()
call from stream_dir() anymore.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Wed Apr  6 17:09:59 UTC 2022 on sn-devel-184