chef_acl provider updates the acls unnecessarily

[ckaushik]

All of our chef runs are updating ACLs every single time because the acl values are arrays and they are compared without sorting

Example chef run output -

update acl environments/environment at environments/environment
15:08:34.045 create: update groups from ["admins", "prod", "clients", "our"] to ["our", "admins", "prod", "clients"]�
15:08:34.045 �read: update groups from ["clients", "admins", "users", "our"] to ["our", "clients", "admins", "users"]�
15:08:34.046 �update, delete, grant: update groups from ["admins", "our"] to ["our", "admins"]�

Solution: Make the comparision insensitive to order