Releasing igmpproxy serialization fix, apparently current master does not have it.

Change-Id: Ib131cf091f048c8557290ba270e9fc9eafbac7a2
diff --git a/VERSION b/VERSION
index c23c9d6..b1387ec 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.1.0-dev12
+4.1.0-dev13