Update global-jjb to v0.24.6 to prep for v0.25.0

Pulls in jjb-verify job tweaks to ensure v0.25.0 properly triggers
a verify job.

Change-Id: I96e0f918005135abea60e2cc0841d1131a0d76dd
Signed-off-by: Thanh Ha <thanh.ha@linuxfoundation.org>

diff --git a/jjb/global-jjb b/jjb/global-jjb
index c61d85ac2a8d2aa6bacfa4719c5ec89e3c5de88c..18bb0a40f9ba00fd8417b32fbde9593b6d968c53 160000 (submodule)
--- a/jjb/global-jjb
+++ b/jjb/global-jjb
@@ -1 +1 @@
-Subproject commit c61d85ac2a8d2aa6bacfa4719c5ec89e3c5de88c
+Subproject commit 18bb0a40f9ba00fd8417b32fbde9593b6d968c53