gitweb: use filetest to allow ACLs

In commit 46a1385 (gitweb: skip unreadable subdirectories, 2017-07-18)
we forgot to handle non-unix ACLs as well. Fix this.

Signed-off-by: Guillaume Castagnino <casta@xwing.info>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 9208f42..6ac49ea 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -10,6 +10,8 @@
 use 5.008;
 use strict;
 use warnings;
+# handle ACL in file access tests
+use filetest 'access';
 use CGI qw(:standard :escapeHTML -nosticky);
 use CGI::Util qw(unescape);
 use CGI::Carp qw(fatalsToBrowser set_message);