vendor: Move back to upstream KCP (fixes #4407)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4614

lib/connections/kcp_dial.go

@@ -11,9 +11,9 @@ import (
 	"net/url"
 	"time"
 
-	"github.com/AudriusButkevicius/kcp-go"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/protocol"
+	"github.com/xtaci/kcp-go"
 	"github.com/xtaci/smux"
 )
 

lib/connections/kcp_listen.go

@@ -15,9 +15,9 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/AudriusButkevicius/kcp-go"
 	"github.com/AudriusButkevicius/pfilter"
 	"github.com/ccding/go-stun/stun"
+	"github.com/xtaci/kcp-go"
 	"github.com/xtaci/smux"
 
 	"github.com/syncthing/syncthing/lib/config"

lib/connections/kcp_misc.go

@@ -15,8 +15,8 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/AudriusButkevicius/kcp-go"
 	"github.com/AudriusButkevicius/pfilter"
+	"github.com/xtaci/kcp-go"
 	"github.com/xtaci/smux"
 )
 

lib/protocol/benchmark_test.go

@@ -8,8 +8,8 @@ import (
 	"net"
 	"testing"
 
-	"github.com/AudriusButkevicius/kcp-go"
 	"github.com/syncthing/syncthing/lib/dialer"
+	"github.com/xtaci/kcp-go"
 )
 
 func BenchmarkRequestsRawTCP(b *testing.B) {