gitweb: Remove extra "/" in path names for git_get_project_list

Without this change we get a wrong $pfxlen value and the check_export_ok()
checks with with a wrong directory name. Without this patch the below
$projects_list fails with gitweb

$projects_list = "/tmp/a/b/";

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

gitweb/gitweb.perl

@@ -902,6 +902,8 @@ sub git_get_projects_list {
 	if (-d $projects_list) {
 		# search in directory
 		my $dir = $projects_list;
+		# remove the trailing "/"
+		$dir =~ s!/+$!!;
 		my $pfxlen = length("$dir");
 
 		File::Find::find({