Prepare changelog for unreleased 3.4.4

Make sure we can merge 3.4.3 to 3.4 maintenance branch but avoid
changes to trunk between 3.4.2 and 3.4.3 that aren't released in
3.4 maintenance branch are getting lost.

From: Michael Prokop <mprokop@sipwise.com>

debian/changelog

@@ -1,3 +1,10 @@
+ngcp-www-admin (3.4.4) UNRELEASED; urgency=low
+
+  [ Christian Veigl ]
+  * check if peering rule already exists beforehand (mantis:1873)
+
+ -- Michael Prokop <mprokop@sipwise.com>  Fri, 24 Aug 2012 19:01:20 +0200
+
 ngcp-www-admin (3.4.3) unstable; urgency=low
 
   [ Michael Prokop ]