Fix preg_match fail

booking.reports.inc

@@ -707,7 +707,7 @@ function booking_csv_report() {
 				$output[] = _booking_status_generate($value);
 				continue;
 			}
-			ygroup session roles
+			//studygroup ygroup session roles
 			if (preg_match("/session\d+_role/", $key))
 			{
 				$output[] = _booking_studygroup_role_lookup($value);