Mention the fact that environment variables now take precedence over the configuration in the Changelog.

ChangeLog

@@ -18,6 +18,8 @@ StarPU 1.0 (svn revision xxxx)
 ==============================================
 The extensions-again release
 
+  * Make environment variables take precedence over the configuration passed to
+        starpu_init();
   * Add man pages for some of the tools
   * Add reduction mode to starpu_mpi_insert_task
   * Add C++ application example in examples/cpp/