cgmanager.c memory management improvements.
cgmanager.c memory management improvements.

- cgmanager_get_pid_cgroup(): Use NIH memory allocation to avoid crash.
- cgmanager_create(): USE NIH memory allocation to simplify memory
  management.

Signed-off-by: James Hunt <170187ea054fb79d4028574cc7d937f7521ccaae@ubuntu.com>

hallyn/cgmanager-pkg-ubuntu,hustcat/cgmanager,udeved/cgmanager,hallyn/cgmanager-pkg-ubuntu,hallyn/cgmanager,hallyn/cgmanager,hustcat/cgmanager,lxc/cgmanager,lxc/cgmanager,udeved/cgmanager