[common] Download `.chef_databag_secret` to the appropriate location.

```
diff --git a/circle.yml b/circle.yml
index 06eec76..32e137f 100644
--- a/circle.yml
+++ b/circle.yml
@@ -5,6 +5,7 @@ machine:
 dependencies:
   post:
     - bundle exec rake init
+    - wget https://raw.githubusercontent.com/kazu634/dotfiles/master/.chef_databag_secret -O /home/ubuntu/chef/.chef_databag_secret]

 test:
   override:
```
[common] Install `language-pack-ja`.

In order for `circle ci` container to support Japanese locale:

```
diff --git a/site-cookbooks/base/recipes/default.rb b/site-cookbooks/base/recipes/default.rb
index 21c333e..01cd79f 100644
--- a/site-cookbooks/base/recipes/default.rb
+++ b/site-cookbooks/base/recipes/default.rb
@@ -44,6 +44,11 @@ when "ubuntu"
   end
 end

+# for `circle ci` container to support Japanese locale:
+package "language-pack-ja" do
+  action :install
+end
+
 script "Language Settings" do
   interpreter "bash"
```