When generating categories-alpha.xml, always output an </li> even if we

don't have a textual description for a particular port category.

This is the real fix for the bug alluded to in r43602.  It is not clear
to me how more people haven't hit this bug.

en_US.ISO8859-1/htdocs/ports/portindex

@@ -355,8 +355,8 @@ EOF
 	  "<li><a href=\"$key.html\">\u$key</a> <em>($stats{$key})</em>";
 	if ($category_description{$key}{desc}) {
 	  print $moutf " -- " . $category_description{$key}{desc};
-	print $moutf "</li>\n";
 	}
+	print $moutf "</li>\n";
       }
       print $moutf "</ul>\n";
     }