CAS-1347: Missing language keys prevents access should not cause a crash

First commit. Notice the version of EhCache has been changed to avoid tests failure
CAS-1347: Missing language keys prevents access should not cause a crash

Revert the downgrade of the EhCache version to fix EhCache problem in a separate pull request
Merge pull request #325 from leleuj/CAS-1347

CAS-1347: Missing language keys prevents access should not cause a crash