Read trailing data on apply

This was removed by mistake during the direct unpack
PR refactoring.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

diff/apply/apply.go

@@ -19,6 +19,7 @@ package apply
 import (
 	"context"
 	"io"
+	"io/ioutil"
 	"time"
 
 	"github.com/containerd/containerd/content"
@@ -97,6 +98,11 @@ func (s *fsApplier) Apply(ctx context.Context, desc ocispec.Descriptor, mounts [
 		return emptyDesc, err
 	}
 
+	// Read any trailing data
+	if _, err := io.Copy(ioutil.Discard, rc); err != nil {
+		return emptyDesc, err
+	}
+
 	for _, p := range processors {
 		if ep, ok := p.(interface {
 			Err() error