Revert "Update Sprout's default setting for memcached hosts to match the Chef default (local IP rather than hostname)."

This reverts commit 44fa5068fea7bfe5f7fb3c1cd38701a9fc67663d.
Merge pull request #158 from Metaswitch/memcached_default_ip

{Reviewer: Andy} Revert "Update Sprout's default setting for memcached hosts to match the...