gitweb: Always use three argument form of open

gitweb: Always use three argument form of open

From 94638fb6edf3ea693228c680a6a30271ccd77522 Mon Sep 17 00:00:00 2001
From: Jakub Narebski <jnareb@gmail.com>
Date: Mon, 11 May 2009 03:25:55 +0200
Subject: [PATCH] gitweb: Localize magic variable $/

Instead of undefining and then restoring magic variable $/ (input
record separator) for 'slurp mode', localize it.

While at it, state explicitely that "local $/;" makes it undefined, by
using explicit  "local $/ = undef;".

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>