lmtp: Fix segfault occurring when a user turns out to be over quota a…

…t DATA transfer.

The LMTP recipient context was not updated with the final recipient address when
the RCPT command was accepted. This left a dangling struct smtp_address pointer
which triggered the segfault when used.

src/lmtp/lmtp-common.c

@@ -22,6 +22,7 @@ void lmtp_recipient_finish(struct lmtp_recipient *rcpt,
 {
 	trcpt->context = rcpt;
 
+	rcpt->path = trcpt->path;
 	rcpt->rcpt = trcpt;
 	rcpt->index = index;
 	rcpt->rcpt_cmd = NULL;