BUG/MINOR: quic: fix version negotiation packet generation

Fix wrong memcpy usage for source and connection ID in generated Version
Negotiation packet.
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index ca1e44f..2aaf9ba 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -3527,12 +3527,12 @@
 
 	/* source connection id */
 	buf[i++] = pkt->scid.len;
-	memcpy(buf, pkt->scid.data, pkt->scid.len);
+	memcpy(&buf[i], pkt->scid.data, pkt->scid.len);
 	i += pkt->scid.len;
 
 	/* destination connection id */
 	buf[i++] = pkt->dcid.len;
-	memcpy(buf, pkt->dcid.data, pkt->dcid.len);
+	memcpy(&buf[i], pkt->dcid.data, pkt->dcid.len);
 	i += pkt->dcid.len;
 
 	/* supported version */