lnd: fix build for Go 1.6.3, refer to old context package

This commit fixes the build for version 1.6.3 of golang. In go 1.7, the
“context” package was moved into the standard library, however go 1.6.3
doesn’t have that change, so we must refer to the prior WIP package
until a new version of Go is released.

lnd_test.go

@@ -2,13 +2,14 @@ package main
 
 import (
 	"bytes"
-	"context"
 	"fmt"
 	"runtime/debug"
 	"strings"
 	"testing"
 	"time"
 
+	"golang.org/x/net/context"
+
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/roasbeef/btcd/rpctest"
 	"github.com/roasbeef/btcd/wire"

networkharness.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"context"
 	"encoding/hex"
 	"fmt"
 	"io/ioutil"
@@ -14,6 +13,8 @@ import (
 	"strconv"
 	"time"
 
+	"golang.org/x/net/context"
+
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/grpclog"