Vendor in latest containers storage

We want to get support into skopeo for handling
override_kernel_checks so that we can use overlay
backend on RHEL.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

vendor/github.com/containers/storage/drivers/overlayutils/overlayutils.go

@@ -0,0 +1,18 @@
+// +build linux
+
+package overlayutils
+
+import (
+	"errors"
+	"fmt"
+)
+
+// ErrDTypeNotSupported denotes that the backing filesystem doesn't support d_type.
+func ErrDTypeNotSupported(driver, backingFs string) error {
+	msg := fmt.Sprintf("%s: the backing %s filesystem is formatted without d_type support, which leads to incorrect behavior.", driver, backingFs)
+	if backingFs == "xfs" {
+		msg += " Reformat the filesystem with ftype=1 to enable d_type support."
+	}
+	msg += " Running without d_type is not supported."
+	return errors.New(msg)
+}