news: Document domifstat and QoS changes made recently

In cea3715b and d86fd240 I've fixed domifstat and QoS
that was reversed for some types of interfaces. Document this
in the news file.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

docs/news.xml

@@ -39,6 +39,17 @@
     <section title="Improvements">
     </section>
     <section title="Bug fixes">
+      <change>
+        <summary>
+          Fix swapped interface statistics and QoS
+        </summary>
+        <description>
+          Due to internal implementation, reported statistics for
+          some types of interfaces were swapped (RX appeared in
+          TX and vice versa). Similarly, QoS was set in reversed
+          way.
+        </description>
+      </change>
     </section>
   </release>
   <release version="v3.8.0" date="2017-10-04">