Added to vendor

vendor/github.com/Microsoft/hcsshim/unpreparelayer.go

@@ -0,0 +1,27 @@
+package hcsshim
+
+import "github.com/sirupsen/logrus"
+
+// UnprepareLayer disables the filesystem filter for the read-write layer with
+// the given id.
+func UnprepareLayer(info DriverInfo, layerId string) error {
+	title := "hcsshim::UnprepareLayer "
+	logrus.Debugf(title+"flavour %d layerId %s", info.Flavour, layerId)
+
+	// Convert info to API calling convention
+	infop, err := convertDriverInfo(info)
+	if err != nil {
+		logrus.Error(err)
+		return err
+	}
+
+	err = unprepareLayer(&infop, layerId)
+	if err != nil {
+		err = makeErrorf(err, title, "layerId=%s flavour=%d", layerId, info.Flavour)
+		logrus.Error(err)
+		return err
+	}
+
+	logrus.Debugf(title+"succeeded flavour %d layerId=%s", info.Flavour, layerId)
+	return nil
+}