tests/int/delete.bats: fixups

1. __runc does not set $status, so the check is misleading.

2. Add set +eux to the nest.sh script so we can error out early, and see
   what is going on.

3. Doing "echo +io" > cgroup.controllers is giving an error on my
   machine ("sh: write error: Operation not supported"). It is probably
   fine to just enable pids controller.

4. Add status check for runc exec nest.sh

5. Remove the second check for cgroup.threads contents -- it was already
   checked earlier (the output of nest.sh script).

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

tests/integration/delete.bats

@@ -71,7 +71,6 @@ function teardown() {
 
   # create a sub process
   __runc exec -d test_busybox sleep 1d
-  [ "$status" -eq 0 ]
 
   # find the pid of sleep
   pid=$(__runc exec test_busybox ps -a | grep 1d | awk '{print $1}')
@@ -79,8 +78,9 @@ function teardown() {
 
   # create subcgroups
   cat <<EOF > nest.sh
+  set -e -u -x
   cd /sys/fs/cgroup
-  for f in \$(cat cgroup.controllers); do echo +\$f > cgroup.subtree_control; done
+  echo +pids > cgroup.subtree_control
   mkdir foo
   cd foo
   echo threaded > cgroup.type
@@ -88,15 +88,12 @@ function teardown() {
   cat cgroup.threads
 EOF
   cat nest.sh | runc exec test_busybox sh
-  [[ ${output} =~ [0-9]+ ]]
+  [ "$status" -eq 0 ]
+  [[ "$output" =~ [0-9]+ ]]
 
   # check create subcgroups success
   [ -d $CGROUP_PATH/foo ]
 
-  # check cgroup.threads' value
-  runc exec test_busybox cat /sys/fs/cgroup/foo/cgroup.threads
-  [[ ${output} =~ [0-9]+ ]]
-
   # force delete test_busybox
   runc delete --force test_busybox