Support Cinc in kosmos-base

Resolve the client config dir at runtime (Chef::Config[:config_file] /
:client_d_dir) instead of hardcoding /etc/chef, and create client.d when
missing so fresh nodes work.

Reload only the attributes file we just wrote, not the whole client.rb:
reloading client.rb reset chef_server_url and dropped knife-zero's -S (TCP)
override, so later server calls fell back to socketless chefzero and failed
with No socketless Cinc Zero server.

site-cookbooks/kosmos-base/recipes/default.rb

@@ -3,9 +3,19 @@
 # Recipe:: default
 #
 
+# Resolve the client's own config paths so this works for both Chef (/etc/chef)
+# and Cinc (/etc/cinc) rather than hardcoding /etc/chef.
+config_file  = Chef::Config[:config_file]
+client_d_dir = Chef::Config[:client_d_dir]
+
+directory client_d_dir do
+  recursive true
+  mode "0755"
+end
+
 ruby_block "cleanup client.rb" do
   block do
-    fe = Chef::Util::FileEdit.new("/etc/chef/client.rb")
+    fe = Chef::Util::FileEdit.new(config_file)
     # Delete whitelist attribute definitions, everything is defined in attributes.rb
     fe.search_file_delete_line(/^.*_attribute_whitelist.*/)
     fe.search_file_delete_line(/^allowed_.*_attributes.*/)
@@ -13,7 +23,7 @@ ruby_block "cleanup client.rb" do
   end
 end
 
-cookbook_file "/etc/chef/client.d/attributes.rb" do
+cookbook_file "#{client_d_dir}/attributes.rb" do
   source "chef_attributes.rb"
   mode "0644"
   notifies :create, "ruby_block[reload_client_config]", :immediately
@@ -21,7 +31,10 @@ end
 
 ruby_block "reload_client_config" do
   block do
-    Chef::Config.from_file("/etc/chef/client.rb")
+    # Reload only the attribute-persistence config we just wrote. Reloading the
+    # whole client.rb would reset chef_server_url and break knife-zero's -S
+    # (TCP) override, making server calls fall back to socketless chefzero.
+    Chef::Config.from_file("#{client_d_dir}/attributes.rb")
   end
   action :nothing
 end