Author: Sam Hemelryk
MDL-38343 cache: better test server strings
http://git.moodle.org/gw?p=moodle.git;a=commit;h=51e7f0504335bacee074b0f872fcf20bf6fe6dc3
http://github.com/moodle/moodle/commit/51e7f0504335bacee074b0f872fcf20bf6fe6dc3
+ 2.9 en [testservers_desc,cachestore_memcache]
+ 2.9 en [testservers_desc,cachestore_memcached]
+ 2.9 en [testserver_desc,cachestore_mongodb]