Apply timestamp fix (r1630088 r1630094) to jdbc-pool and mention it in changelog.

The VERSION_BUILT filter string is actually not used in any of jdbc-pool source files, so this change does not matter much for the current jdbc-pool.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1631381 13f79535-47bb-0310-9956-ffa450edef68