news: Make changes understandable for users

When reading release notes, patch summary is not always the best
description of what users can expect in new version.  I propose
changing it slightly so that it describes what exactly happens and
when.

However, we do not have to add every single code change to the news
file, that would be ridiculous and unreadable for users.  If the patch
subject needs changes like this one, I'm rather tempted to say that
such changes should not be in the news file at all.  So that would be
the other way how to fix this.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

docs/news.xml

@@ -706,7 +706,7 @@
       </change>
       <change>
         <summary>
-          logical: Need to overwrite/clear more than just first 512 bytes
+          Overwrite (clear) 2 KB instead of just 512 bytes when initializing logical device
         </summary>
       </change>
       <change>