debian packaging remove duplicate change entry

Author: jef-n

debian/changelog

@@ -1,16 +1,13 @@
-qgis (2.15.0) unstable; urgency=medium
-
-  * Add dependency to python-future
-
- -- Matthias Kuhn <matthias@opengis.ch>  Tue, 22 Mar 2016 11:17:23 +0100
-
 qgis (2.15.0) UNRELEASED; urgency=medium
 
   [ Jürgen E. Fischer ]
   * New development version 2.15 after branch of 2.14
   * drop ubuntu utopic
   * refine GSL build dependency
 
+  [ Matthias Kuhn ]
+  * Add dependency to python-future
+
   [ Bas Couwenberg ]
   * Fix removal of obsolete diversions for bother the grass plugin & provider.
     (closes: #817176)