elasticsearch: create required folders

Closes Homebrew/homebrew#19994.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/elasticsearch.rb

@@ -39,6 +39,11 @@ class Elasticsearch < Formula
       rm_rf "#{prefix}/target/"
     end
 
+    # Make sure runtime directories exist
+    (var/"elasticsearch/#{cluster_name}").mkpath
+    (var/"log/elasticsearch").mkpath
+    (var/"lib/elasticsearch/plugins").mkpath
+
     # Set up ElasticSearch for local development:
     inreplace "#{prefix}/config/elasticsearch.yml" do |s|
       # 1. Give the cluster a unique name