Remove default attributes ['config']['owner'] and ['config']['group']

These attributes are redundant in the default.rb attribute file since they cause
a confusion about what are default values of `owner` and `group` params
of `counsul_config` resource.

Due to Poise inversion options, the node's attribute will always have a precedence.
They are designed to be used by cookbook end-users in their wrapper cookbooks.

We already have default values defined in the resource itself, so we can
remove default attributes without any effect.

.kitchen.dokken.yml

@@ -102,7 +102,6 @@ suites:
       consul:
         config: &default-config
           owner: root
-          group: consul
           bootstrap: true
           server: true
           datacenter: FortMeade

.kitchen.yml

@@ -26,7 +26,6 @@ suites:
       consul:
         config: &default-config
           owner: root
-          group: consul
           ui: true
           bootstrap: true
           server: true

README.md

@@ -85,7 +85,10 @@ end
 ```
 
 ### Security
-The default recipe makes the Consul configuration writable by the consul service user to avoid breaking existing implementations. You can make this more secure by setting the `node['consul']['config']` attribute to `root`, or set the `owner` property of `consul_config` explicitly:
+The default recipe makes the Consul configuration writable by the consul service
+user to avoid breaking existing implementations. You can make this more secure
+by setting the `node['consul']['config']['owner']` attribute to `root`, or set
+the `owner` property of `consul_config` explicitly:
 
 ```ruby
 # attributes file

attributes/default.rb

@@ -10,8 +10,6 @@
 default['consul']['service_group'] = 'consul'
 default['consul']['create_service_user'] = true
 
-default['consul']['config']['owner'] = 'consul'
-default['consul']['config']['group'] = 'consul'
 default['consul']['config']['path'] = join_path config_prefix_path, 'consul.json'
 default['consul']['config']['data_dir'] = data_path
 default['consul']['config']['ca_file'] = join_path config_prefix_path, 'ssl', 'CA', 'ca.crt'