Fixes

• There was a bad assumption with respect to ordering when multiple controllers are aggregated under one directory. For example, "cpu,cpuacct". The code assumed that the ordering would be consistent wherever it is exposed -- specifically in the cgroup dir names and the /proc//cgroup file contents -- but feedback from the wild indicates that is a bad assumption. Repair the infelicity by checking all permutations of the list to find the one which actually matches the cgroup directory name.