Fixed enumerator build for openbsd (unsupported operation)

enumerator/usb_openbsd.go

@@ -0,0 +1,12 @@
+//
+// Copyright 2014-2020 Cristian Maglie. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+
+package enumerator
+
+func nativeGetDetailedPortsList() ([]*PortDetails, error) {
+	// TODO
+	return nil, &PortEnumerationError{}
+}