Merge changes from Pool 2 to r1609323.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1609329 13f79535-47bb-0310-9956-ffa450edef68
Merge changes from DBCP 2 up to r1609329.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1609331 13f79535-47bb-0310-9956-ffa450edef68