test_util_check_env "cgroup sandbox" test fails with cgmanager installed

[Martin Pitt]

For a few days we now install cgmanager as a dependency of systemd-shim, i. e. essentially by default. This caused one upstart test to fail:

make[4]: Entering directory '/tmp/adt-run.8AaKHU/build.Nsv/upstart-1.13.1/test'
(null): I am in freezer cgroup: /
(null):setup_cgroup_sandbox: failed to create cgroup cpuset:upstart-test-tyr7jI
(null):dbus_error.c:69: Unhandled error from nih_dbus_error_raise: invalid request
ok 1 - test environment
ok 2 - checking for overlayfs
ok 3 - checking for cgmanager
not ok 4 - cgroup sandbox
/bin/bash: line 5: 10695 Aborted (core dumped) ${dir}$tst
FAIL: test_util_check_env
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1 of 1 test failed
Please report to <email address hidden>
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full log on https://jenkins.qa.ubuntu.com/job/utopic-adt-upstart/66/ARCH=i386,label=adt/consoleText

jodh | hallyn_: I don't think the upstart tests should be managing that. Clearly, something changed in the env to now cause this test to fail in the jenkins env (works fine on the buildd's and locally). But, the test should prolly check to see if they are already in a cgroup and if not, print a warning and skip that test (as we do for overlayfs).
hallyn_ | oh, well, the test doesn't run if cgmanager isn't installed
hallyn_ | so, that's what changed :)
hallyn_ | jodh: so teh testcase could simply try 'cgm create memory xxx', and if that fails, say "sorry i'm not in my own cgroup; exit"