Remove workarounds for old systemd bugs

These are now resolved:

Were are now later than systemd v231
https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1497420
https://github.com/lxc/lxc/issues/713

Change-Id: I3c427bc670815ee5bac677925b56df644f460271

tasks/lxc_post_install.yml

@@ -74,62 +74,6 @@
   tags:
     - lxc-config
 
-# NOTE(hwoarang): The previous task only affected newly created services.
-# However, for particular systemd versions like v228 the default one for
-# started scopes is 512
-# See https://github.com/systemd/systemd/commit/9ded9cd14cc03c67291b10a5c42ce5094ba0912f
-# This has later been fixed in v231
-# https://github.com/systemd/systemd/commit/79baeeb96d58676853521e10a358e85d83dac7f1
-# The only way to change the value for already started services and scopes is
-# by using the sysfs interface. Moreover, it appears that lxc places itself into the
-# init.scope group which is being created during boot and as such it always uses
-# the default value. There are variours reports that the init.scope breaks things
-# for LXC such as
-# https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1497420
-# https://github.com/lxc/lxc/issues/713
-# https://bugs.archlinux.org/index.php?do=details&action=details.addvote&task_id=47303
-# In any case, it's best to also edit the pids controller to ensure that a
-# better max value is used in the init.scope
-- name: Check that the init.scope support the pid controller
-  stat:
-    path: "/sys/fs/cgroup/pids/init.scope/pids.max"
-  register: _init_scope_pid
-  tags:
-    - lxc-config
-
-- block:
-    - name: Get init.scope pids.max value
-      slurp:
-        src: "/sys/fs/cgroup/pids/init.scope/pids.max"
-      register: init_scope_cgroup_pids_max
-      changed_when: false
-
-    # NOTE(cloudnull): The "shell" module is being used instead of "copy" with
-    #                  content as we need direct write access to the sysFS.
-    - name: Set systemd pids.max in init.scope
-      shell: "echo {{ lxc_default_tasks_max }} > /sys/fs/cgroup/pids/init.scope/pids.max"
-      when:
-        - (init_scope_cgroup_pids_max.content | b64decode) != lxc_default_tasks_max
-      tags:
-        - skip_ansible_lint
-  rescue:
-    - name: Notice regarding setting the init.scope/pids.max
-      debug:
-        msg: |
-          Failed writing to "/sys/fs/cgroup/pids/init.scope/pids.max". While
-          we prefer setting this option it's not required. See the following
-          issues on why this is desired and what can be done when the cgroup
-          hierarchy exists.
-            * https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1497420
-            * https://github.com/lxc/lxc/issues/713
-            * https://bugs.archlinux.org/index.php?do=details&action=details.addvote&task_id=47303
-  when: _init_scope_pid.stat.exists
-  tags:
-    - lxc-config
-
-# Ensure apparmor reindex runs before other things that may fail
-- meta: flush_handlers
-
 - name: Tuning kernel for lxc
   sysctl:
     name: "{{ item.key }}"