Add chromeos-bsp-mistral to upstart oom score exceptions

This check is breaking mistral-cq.
See:
https://luci-milo.appspot.com/ui/p/chromeos/builders/cq/mistral-cq/b8840249940947384448/overview

BUG=b:195145703
TEST=None

Change-Id: Icb97ec6349b7a9f98720c62c28e50c5af9ce7b53
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3064841
Tested-by: Dennis Kempin <denniskempin@google.com>
Owners-Override: Dennis Kempin <denniskempin@google.com>
Reviewed-by: George Engelbrecht <engeg@google.com>
Reviewed-by: Aileen Cheng <chengaileen@google.com>
Commit-Queue: Aileen Cheng <chengaileen@google.com>
diff --git a/hooks/install/check-upstart-scripts.sh b/hooks/install/check-upstart-scripts.sh
index e36500d..34e4205 100755
--- a/hooks/install/check-upstart-scripts.sh
+++ b/hooks/install/check-upstart-scripts.sh
@@ -68,6 +68,7 @@
   chromeos-base/chromeos-bsp-endeavour-private|\
   chromeos-base/chromeos-bsp-gale|\
   chromeos-base/chromeos-bsp-hatch-private|\
+  chromeos-base/chromeos-bsp-mistral|\
   chromeos-base/chromeos-bsp-mobbase|\
   chromeos-base/chromeos-bsp-zork-private|\
   chromeos-base/chromeos-chrome|\