remove all trailing blank lines

by running this command:
git ls-files -z | xargs -0 perl -pi -0777 -e 's/\n\n+$/\n/'
This is in preparation for a more strict make syntax-check
rule that will detect trailing blank lines.

tests/xml2sexprdata/xml2sexpr-fv-serial-pty.xml

@@ -36,4 +36,3 @@
     <graphics type='vnc' port='5917' keymap='ja'/>
   </devices>
 </domain>
-