w/o this I would see:
```
unexpected file format for /proc/self/cgroup - ""
```
while running the cgroup tests
Signed-off-by: Doug Davis <dug@us.ibm.com>
This fixes a few misuses of `deleteAllContainers()` cleanup
method in integration-cli suite by moving call to the
beginning of the method and guaranteeing their execution
(including panics) with `defer`s.
Also added some forgotten cleanup calls while I'm at it.
Signed-off-by: Ahmet Alp Balkan <ahmetalpbalkan@gmail.com>