vfs_shadow_copy2: remove async getxattrat

vfs_shadow_copy2: remove async getxattrat

vfswrap_getxattrat_send() is handle based using smb_fname->fsp. As
the open of smb_fname->fsp was processed by this module, the handle
is already correctly opened on the file in the snapshot. In the end
this means we can just call directly call the next function here.

Note that the same reasoning might apply to other modules that use
vfs_not_implemented_getxattrat_send(), but checking and adjusting those is a job
for another day. Currently they will continue to go via the sync fallback of the
caller.

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Mon Feb 28 20:53:35 UTC 2022 on sn-devel-184