add package.html for the build to pass

git-svn-id: http://svn.terracotta.org/svn/ehcache@7795 b9324663-ca0f-0410-8574-be9b3887307d
Tag ehcache-2.7.3 from 4.0.3-rc branch

git-svn-id: http://svn.terracotta.org/svn/ehcache@7796 b9324663-ca0f-0410-8574-be9b3887307d