QA-591: give ISO dates priority in parsing

git-svn-id: http://svn.terracotta.org/svn/ehcache@7938 b9324663-ca0f-0410-8574-be9b3887307d
merge rev. 7938

git-svn-id: http://svn.terracotta.org/svn/ehcache@7939 b9324663-ca0f-0410-8574-be9b3887307d