Migrate Sirupsen to sirupsen.

vendor/github.com/docker/libcompose/docker/image/image.go

@@ -7,7 +7,6 @@ import (
 	"io"
 	"os"
 
-	"github.com/Sirupsen/logrus"
 	"github.com/docker/distribution/reference"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/client"
@@ -15,6 +14,7 @@ import (
 	"github.com/docker/docker/pkg/term"
 	"github.com/docker/docker/registry"
 	"github.com/docker/libcompose/docker/auth"
+	"github.com/sirupsen/logrus"
 	"golang.org/x/net/context"
 )
 
@@ -22,7 +22,7 @@ import (
 func Exists(ctx context.Context, clt client.ImageAPIClient, image string) (bool, error) {
 	_, err := InspectImage(ctx, clt, image)
 	if err != nil {
-		if client.IsErrImageNotFound(err) {
+		if client.IsErrNotFound(err) {
 			return false, nil
 		}
 		return false, err