In order to support changing other attributes than the file size in
fuse_setattr(), we have to give each its own independent branch.  This
also applies to the only attribute we do support right now.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210625142317.271673-4-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>