Prevent ehcache from phoning home for statistics purposes

www.terracottatech.com:80 and org01.terracotta.org:80 network activities perceived on a Stash instance are due to ehcache (a cache component used in Stash) phoning home for statistics purposes.

These calls should be able to be blacklisted safely by the client on their firewalls without loss of functionality to Stash.

We're checking through this issue whether to completely disable these calls.