s3:adouble: rewrite ad_open_rsrc() as adouble_open_rsrc_fsp() using create_internal_fsp()

s3:adouble: rewrite ad_open_rsrc() as adouble_open_rsrc_fsp() using create_internal_fsp()

"._" AppleDouble files are hidden by vfs_fruit by default, so there's no
need to go through a full SMB_VFS_CREATE_FILE() for them.

They don't need an smbXsrv_open_global.tdb entry nor a locking.tdb
entry, so we just open them with fd_openat().

This avoids a recursion deadlock in get_share_mode_lock() when closing
the ':AFP_Resource' stream.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>