Remove now useless QUIC method AdjustErrorForVersion() which has been a no-op for some time.

net/quic/core/quic_connection.cc

Index: net/quic/core/quic_connection.cc
diff --git a/net/quic/core/quic_connection.cc b/net/quic/core/quic_connection.cc
index 9342a66da4a880b676390130f4c18eb7798a0315..a73e2b8296ae9729388c1f6e762ac7424a1f2a4b 100644
--- a/net/quic/core/quic_connection.cc
+++ b/net/quic/core/quic_connection.cc
@@ -1230,8 +1230,8 @@ void QuicConnection::SendRstStream(QuicStreamId id,
                                    QuicStreamOffset bytes_written) {
   // Opportunistically bundle an ack with this outgoing packet.
   ScopedPacketBundler ack_bundler(this, SEND_ACK_IF_PENDING);
-  packet_generator_.AddControlFrame(QuicFrame(new QuicRstStreamFrame(
-      id, AdjustErrorForVersion(error, version()), bytes_written)));
+  packet_generator_.AddControlFrame(
+      QuicFrame(new QuicRstStreamFrame(id, error, bytes_written)));
 
   if (error == QUIC_STREAM_NO_ERROR) {
     // All data for streams which are reset with QUIC_STREAM_NO_ERROR must