Update Pool2 to latest trunk to pick up fixes/updates for:
- memory leak via the Evictor
- potential although unlikely threading issue
- application provided eviction policies
- POOL-270, POOL-276 

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1627027 13f79535-47bb-0310-9956-ffa450edef68