upgrade of concurrentlinkedhashmap_lru

as discussed some time ago on grails-dev I've updated the dependency of concurrentlinkedhashmap_lru to 1.3.1.

Since this change must be in sync with the same update for grails-data-mapping, please apply the both pull-requests at the same time. Also, any new build of grails-core needs to have a updated 1.1.4-SNAPSHOT of grails-datastore-core deployed to repo.grails.org.

The core issue is that concurrentlinkedhashmap_lru 1.2_jdk5 and 1.3.1 are not backwards compatible.