ifupdownconfig: add missing config module ifupdownconfig.py

Add back missing ifupdown/ifupdownconfig.py.
fixes a cherry-pick error.

Fixes 0582f185ed ("ifupdown2: address: squash addr config and process
them on the youngest sibling")
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>

ifupdown/ifupdownconfig.py

@@ -0,0 +1,14 @@
+#!/usr/bin/env python
+#
+# Copyright 2015 Cumulus Networks, Inc. All rights reserved.
+#
+# Author: Roopa Prabhu, roopa@cumulusnetworks.com
+#
+#
+
+class ifupdownConfig():
+
+	def __init__(self):
+		self.conf = {}
+
+config = ifupdownConfig()