tests: use filesystem dir until I figure out why ephemerals dirs are having trouble

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1457135 13f79535-47bb-0310-9956-ffa450edef68
SOLR-4311: Admin UI - Optimize Caching Behaviour (merge r1457143)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1457144 13f79535-47bb-0310-9956-ffa450edef68