smbd: return correct error for compound related requests that went async

smbd: return correct error for compound related requests that went async

For a compound related request chain of eg CREATE+NOTIFY+GETINFO, the NOTIFY
will typically go async. When this is noted in smbd_smb2_request_pending_queue()
the pending async tevent_req is cancelled which means we return
NT_STATUS_CANCELLED to the client while Windows returns
NT_STATUS_INTERNAL_ERROR.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15697

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