Merge pull request #5463 from tianon/hack-dind-cgroup

Update hack/dind to mount cgroups on "/cgroup" instead of "/sys/fs/cgroup" for better compatibility

hack/dind

@@ -14,7 +14,7 @@ set -e
 export container=docker
 
 # First, make sure that cgroups are mounted correctly.
-CGROUP=/sys/fs/cgroup
+CGROUP=/cgroup
 
 mkdir -p "$CGROUP"