cgroup: call cgroups by the binary name and pid instead of just pid

This makes it slightly easier to identify what's going on by looking
at the control group hierarchy.

BUG=none
TEST=run trybot with pretty much anything

Change-Id: Ie986fa65e9bf95d95403771cdaef98c90a01725a
Reviewed-on: https://gerrit.chromium.org/gerrit/16055
Reviewed-by: Zdenek Behan <zbehan@chromium.org>
Tested-by: Brian Harring <ferringb@chromium.org>
Commit-Ready: Brian Harring <ferringb@chromium.org>
diff --git a/scripts/cbuildbot.py b/scripts/cbuildbot.py
index 335ab60..1a6367e 100644
--- a/scripts/cbuildbot.py
+++ b/scripts/cbuildbot.py
@@ -979,7 +979,7 @@
   with cleanup.EnforcedCleanupSection() as critical_section:
     with sudo.SudoKeepAlive():
       with cros_lib.AllowDisabling(options.cgroups,
-                                   cgroups.ContainChildren, 'cbuildbot'):
+                                   cgroups.SimpleContainChildren, 'cbuildbot'):
         # Mark everything between EnforcedCleanupSection and here as having to
         # be rolled back via the contextmanager cleanup handlers.  This ensures
         # that sudo bits cannot outlive cbuildbot, that anything cgroups