debian: Clean up to look like other osmocom projects

Change-Id: Id71699642b799f5b2f8f3b794b9493ddaeb70cc0
diff --git a/debian/compat b/debian/compat
index 7f8f011..ec63514 100644
--- a/debian/compat
+++ b/debian/compat
@@ -1 +1 @@
-7
+9