making a directory to cd into, for splunk

chef/cookbooks/common/recipes/splunk.rb

 unless system "splunk status"
   execute "Download splunk" do
+    command "mkdir -p /tmp/install"
     command "cd /tmp/install && wget 'http://www.splunk.com/index.php/download_track?file=4.1.5/linux/splunk-4.1.5-85165-Linux-x86_64.tgz&ac=&wget=true&name=wget&typed=releases'"
   end