Use new_resource to read attribute
Use new_resource to read attribute

This fixes the following error:
    NameError
    ---------
    undefined local variable or method `restart_policy' for

Signed-off-by: Hervé Werner <bba7f28c9d422bfe15d862e6b87ae4dbf5a527bd@ledger.fr>

chef-cookbooks/docker,chef-cookbooks/docker,chef-cookbooks/docker