drop old refs/tryjobs/ namespace

This was used by old cros tryjob tooling.

Change-Id: I6f3409a5fc406453caeae788d9d13c8f439fdd28
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/+/6443758
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>

project.config

diff --git a/project.config b/project.config
index 98c34bc..51c0095 100644
--- a/project.config
+++ b/project.config
@@ -88,8 +88,6 @@
 [access "refs/for/refs/*"]
 	push = group chromeos-committers
 	pushMerge = group chromeos-bots
-[access "refs/tryjobs/*"]
-	delete = group chromeos-committers
 [access "refs/sandbox/*"]
 	create = group chromeos-gerrit-sandbox-access
 	forgeCommitter = group chromeos-gerrit-sandbox-access