build: bump to Go 1.10

Bumps the build to use Go 1.10, which allows us to drop the forked tar
package.

Signed-off-by: Stephen J Day <stephen.day@docker.com>

archive/strconv.go

@@ -23,7 +23,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/dmcgowan/go-tar"
+	"archive/tar"
 )
 
 // Forked from https://github.com/golang/go/blob/master/src/archive/tar/strconv.go

archive/tar.go

@@ -17,6 +17,7 @@
 package archive
 
 import (
+	"archive/tar"
 	"context"
 	"fmt"
 	"io"
@@ -31,7 +32,6 @@ import (
 
 	"github.com/containerd/containerd/log"
 	"github.com/containerd/continuity/fs"
-	"github.com/dmcgowan/go-tar"
 	"github.com/pkg/errors"
 )
 

archive/tar_unix.go

@@ -19,13 +19,13 @@
 package archive
 
 import (
+	"archive/tar"
 	"context"
 	"os"
 	"sync"
 	"syscall"
 
 	"github.com/containerd/continuity/sysx"
-	"github.com/dmcgowan/go-tar"
 	"github.com/opencontainers/runc/libcontainer/system"
 	"github.com/pkg/errors"
 	"golang.org/x/sys/unix"

archive/tar_windows.go

@@ -19,6 +19,7 @@
 package archive
 
 import (
+	"archive/tar"
 	"bufio"
 	"context"
 	"encoding/base64"
@@ -36,7 +37,6 @@ import (
 	"github.com/Microsoft/hcsshim"
 	"github.com/containerd/containerd/log"
 	"github.com/containerd/containerd/sys"
-	"github.com/dmcgowan/go-tar"
 )
 
 const (