gitweb: use fullname as hash_base in heads link

Otherwise, if names are manipulated for display, the link will point to
the wrong head.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Acked-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gitweb/gitweb.perl

@@ -4960,7 +4960,7 @@ sub git_heads_body {
 		      "<td class=\"link\">" .
 		      $cgi->a({-href => href(action=>"shortlog", hash=>$ref{'fullname'})}, "shortlog") . " | " .
 		      $cgi->a({-href => href(action=>"log", hash=>$ref{'fullname'})}, "log") . " | " .
-		      $cgi->a({-href => href(action=>"tree", hash=>$ref{'fullname'}, hash_base=>$ref{'name'})}, "tree") .
+		      $cgi->a({-href => href(action=>"tree", hash=>$ref{'fullname'}, hash_base=>$ref{'fullname'})}, "tree") .
 		      "</td>\n" .
 		      "</tr>";
 	}