smbd: Fix use-after-free from exit_server_common()

We need to keep the smbXsrv_connection structures around until all
pending requests have had their chance to clean up behind them. If you
look at srv_send_smb(), it's exactly prepared already to just drop
anything on the floor when the transport has been declared dead:

	if (!NT_STATUS_IS_OK(xconn->transport.status)) {
		 * we're not supposed to do any io
		return true;


Signed-off-by: Volker Lendecke <>
Reviewed-by: Stefan Metzmacher <>

Autobuild-User(master): Stefan Metzmacher <>
Autobuild-Date(master): Thu Aug  1 15:39:13 UTC 2019 on sn-devel-184

(cherry picked from commit c226dc6e)
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