Debian packaging: Use NEWS.markdown as upstream changelog

No more install it as separate documentation.

debian/changelog

@@ -6,6 +6,7 @@ xen-tools (4.6.3~dev-1) UNRELEASED; urgency=medium
       and fixed by Yuri Sakhno, thanks!)
     + Fixes typo found by lintian.
   * Declare compliance with Debian Policy 3.9.8. (No changes needed.)
+  * Use NEWS.markdown as upstream changelog, don't install it as docs.
 
  -- Axel Beckert <abe@debian.org>  Thu, 24 Dec 2015 11:54:24 +0100
 

debian/docs

@@ -2,4 +2,3 @@ AUTHORS
 README.markdown
 SUPPORT.markdown
 TODO.markdown
-NEWS.markdown

debian/rules

@@ -8,4 +8,7 @@
 override_dh_auto_test:
 	make non-author-test
 
+override_dh_installchangelogs:
+	dh_installchangelogs NEWS.markdown
+
 override_dh_auto_build: