paper: remove css hack that made .branchname look like .branchhead

There's a visual difference in hgweb between one changeset that is the tip of
its branch and another that simply belongs to that branch. But paper theme
ignored this difference on changeset page and used to always use "branchname"
css class, be that changeset the tip of its branch or not. That has been
recently fixed, so this piece of css is not needed anymore.

mercurial/templates/static/style-paper.css

@@ -192,10 +192,6 b' ul#graphnodes .branchhead {'
   vertical-align: baseline;
 }
 
-h3 .branchname {
-  font-size: 80%;
-}
-
 /* Common */
 pre { margin: 0; }