Fixed incorrect "ark" parameters for the installation directory

If you set a custom installation directory using the :dir attribute, the cookbook still installs ElasticSearch in /usr/local/. This is because the call to ark that downloads and installs ElasticSearch doesn't include the necessary parameters to actually place the unpacked files in a custom location.

This patch updates the default cookbook to properly configure ark when using a custom directory.

Closes #80

recipes/default.rb

@@ -65,13 +65,18 @@
 
 # Download, extract, symlink the elasticsearch libraries and binaries
 #
+ark_prefix_root = node.elasticsearch[:dir] || node.ark[:prefix_root]
+ark_prefix_home = node.elasticsearch[:dir] || node.ark[:prefix_home]
+
 ark "elasticsearch" do
   url   node.elasticsearch[:download_url]
   owner node.elasticsearch[:user]
   group node.elasticsearch[:user]
   version node.elasticsearch[:version]
   has_binaries ['bin/elasticsearch', 'bin/plugin']
   checksum node.elasticsearch[:checksum]
+  prefix_root   ark_prefix_root
+  prefix_home   ark_prefix_home
 
   notifies :start,   'service[elasticsearch]'
   notifies :restart, 'service[elasticsearch]'