Build for ubuntu xenial

Change-Id: I96c8c34ae62ac92e0437dbcb7448ab11e161c98b
diff --git a/debian/gbp.conf b/debian/gbp.conf
index 7bf5959..d6f9d4f 100644
--- a/debian/gbp.conf
+++ b/debian/gbp.conf
@@ -1,6 +1,6 @@
 [DEFAULT]
 upstream-branch = master
-debian-branch = debian/unstable
+debian-branch = debian/xenial
 upstream-tag = %(version)s
 compression = xz