Updates grab-queue: 297ece4 Decrease default limit_concurrent

diff --git a/grab-queue b/grab-queue
index d312f535406ad271ae0e78889710c9048f6ec5e8..297ece41feb8aa54d8d5fb47623418d9421291e7 160000 (submodule)
--- a/grab-queue
+++ b/grab-queue
@@ -1 +1 @@
-Subproject commit d312f535406ad271ae0e78889710c9048f6ec5e8
+Subproject commit 297ece41feb8aa54d8d5fb47623418d9421291e7