routerrpc: remove deprecated SendPayment, SendToRoute, TrackPayment impls

diff --git a/lnrpc/routerrpc/router_server.go b/lnrpc/routerrpc/router_server.go
index e3ac207..23e5ace 100644
--- a/lnrpc/routerrpc/router_server.go
+++ b/lnrpc/routerrpc/router_server.go
@@ -96,10 +96,6 @@ var (
 			Entity: "offchain",
 			Action: "write",
 		}},
-		"/routerrpc.Router/SendToRoute": {{
-			Entity: "offchain",
-			Action: "write",
-		}},
 		"/routerrpc.Router/TrackPaymentV2": {{
 			Entity: "offchain",
 			Action: "read",
@@ -144,14 +140,6 @@ var (
 			Entity: "offchain",
 			Action: "read",
 		}},
-		"/routerrpc.Router/SendPayment": {{
-			Entity: "offchain",
-			Action: "write",
-		}},
-		"/routerrpc.Router/TrackPayment": {{
-			Entity: "offchain",
-			Action: "read",
-		}},
 		"/routerrpc.Router/HtlcInterceptor": {{
 			Entity: "offchain",
 			Action: "write",
diff --git a/lnrpc/routerrpc/router_server_deprecated.go b/lnrpc/routerrpc/router_server_deprecated.go
index a08cafc..4b3ed63 100644
--- a/lnrpc/routerrpc/router_server_deprecated.go
+++ b/lnrpc/routerrpc/router_server_deprecated.go
@@ -2,125 +2,11 @@ package routerrpc
 
 import (
 	"context"
-	"encoding/hex"
-	"errors"
-	"fmt"
 
-	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
 )
 
-// legacyTrackPaymentServer is a wrapper struct that transforms a stream of main
-// rpc payment structs into the legacy PaymentStatus format.
-type legacyTrackPaymentServer struct {
-	Router_TrackPaymentServer
-}
-
-// Send converts a Payment object and sends it as a PaymentStatus object on the
-// embedded stream.
-func (i *legacyTrackPaymentServer) Send(p *lnrpc.Payment) error {
-	var state PaymentState
-	switch p.Status {
-	case lnrpc.Payment_IN_FLIGHT:
-		state = PaymentState_IN_FLIGHT
-	case lnrpc.Payment_SUCCEEDED:
-		state = PaymentState_SUCCEEDED
-	case lnrpc.Payment_FAILED:
-		switch p.FailureReason {
-		case lnrpc.PaymentFailureReason_FAILURE_REASON_NONE:
-			return fmt.Errorf("expected fail reason")
-
-		case lnrpc.PaymentFailureReason_FAILURE_REASON_TIMEOUT:
-			state = PaymentState_FAILED_TIMEOUT
-
-		case lnrpc.PaymentFailureReason_FAILURE_REASON_NO_ROUTE:
-			state = PaymentState_FAILED_NO_ROUTE
-
-		case lnrpc.PaymentFailureReason_FAILURE_REASON_ERROR:
-			state = PaymentState_FAILED_ERROR
-
-		case lnrpc.PaymentFailureReason_FAILURE_REASON_INCORRECT_PAYMENT_DETAILS:
-			state = PaymentState_FAILED_INCORRECT_PAYMENT_DETAILS
-
-		case lnrpc.PaymentFailureReason_FAILURE_REASON_INSUFFICIENT_BALANCE:
-			state = PaymentState_FAILED_INSUFFICIENT_BALANCE
-
-		default:
-			return fmt.Errorf("unknown failure reason %v",
-				p.FailureReason)
-		}
-	default:
-		return fmt.Errorf("unknown state %v", p.Status)
-	}
-
-	preimage, err := hex.DecodeString(p.PaymentPreimage)
-	if err != nil {
-		return err
-	}
-
-	legacyState := PaymentStatus{
-		State:    state,
-		Preimage: preimage,
-		Htlcs:    p.Htlcs,
-	}
-
-	return i.Router_TrackPaymentServer.Send(&legacyState)
-}
-
-// TrackPayment returns a stream of payment state updates. The stream is
-// closed when the payment completes.
-func (s *Server) TrackPayment(request *TrackPaymentRequest,
-	stream Router_TrackPaymentServer) error {
-
-	legacyStream := legacyTrackPaymentServer{
-		Router_TrackPaymentServer: stream,
-	}
-	return s.TrackPaymentV2(request, &legacyStream)
-}
-
-// SendPayment attempts to route a payment described by the passed
-// PaymentRequest to the final destination. If we are unable to route the
-// payment, or cannot find a route that satisfies the constraints in the
-// PaymentRequest, then an error will be returned. Otherwise, the payment
-// pre-image, along with the final route will be returned.
-func (s *Server) SendPayment(request *SendPaymentRequest,
-	stream Router_SendPaymentServer) error {
-
-	if request.MaxParts > 1 {
-		return errors.New("for multi-part payments, use SendPaymentV2")
-	}
-
-	legacyStream := legacyTrackPaymentServer{
-		Router_TrackPaymentServer: stream,
-	}
-	return s.SendPaymentV2(request, &legacyStream)
-}
-
-// SendToRoute sends a payment through a predefined route. The response of this
-// call contains structured error information.
-func (s *Server) SendToRoute(ctx context.Context,
-	req *SendToRouteRequest) (*SendToRouteResponse, error) {
-
-	resp, err := s.SendToRouteV2(ctx, req)
-	if err != nil {
-		return nil, err
-	}
-
-	if resp == nil {
-		return nil, nil
-	}
-
-	// Need to convert to legacy response message because proto identifiers
-	// don't line up.
-	legacyResp := &SendToRouteResponse{
-		Preimage: resp.Preimage,
-		Failure:  resp.Failure,
-	}
-
-	return legacyResp, nil
-}
-
 // QueryProbability returns the current success probability estimate for a
 // given node pair and amount.
 func (s *Server) QueryProbability(_ context.Context,