Filter output by project id (when specified).

Change-Id: Ieeaa924a29ff297b74e4e2b0a68c8eae4c3e86ca
diff --git a/export/repositories.csv.php b/export/repositories.csv.php
index 36935d1..41ea361 100644
--- a/export/repositories.csv.php
+++ b/export/repositories.csv.php
@@ -26,17 +26,28 @@
 require_once dirname(__FILE__) . '/../classes/debug.php';
 require_once dirname(__FILE__) . '/../classes/database.inc';
 
-$sql = "
+$where = array("1 = 1");
+$args = array();
+
+if ($id = @$_GET['id']) {
+	$where[] = "project = ':id:'";
+	$args[':id:'] = $id;
+}
+
+$where = implode(" and ", $where);
+
+$sql = <<< EOQ
  select
   project, path
  from GitRepo
+ where $where
  order by project
-";
+EOQ;
 
 $fp = fopen('php://output', 'w');
 fwrite($fp, "# NOT API; this script is subject to change without notice.\n");
 
-query('dashboard', $sql, array(), function($row) use (&$fp) {
+query('dashboard', $sql, $args, function($row) use (&$fp) {
  $project = $row['project'];
  $path = trim($row['path']);
  if (preg_match('/^\/gitroot\//',$path))