Return ECGROUPNOTEQUAL to indicate partial create success

Return ECGROUPNOTEQUAL to indicate partial create success

Return ECGROUPNOTEQUAL when copying controller parameters fails--
this allows callers to differentiate between cgroup creation failures and
controller configuration failures, and makes explicit that this function
can return an error code but still have created the cgroup.  Callers,
such as cgroup_create_cgroup_from_parent(), can now explicitly ignore
(the unfortunately expected) controller configuration errors.

Signed-off-by: Eric Brower <ebrower@gmail.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval.giani@gmail.com>