Eliminated possibility that DefaultPoolObject#getIdleTimeMillis() could
return a negative value. Use by pool implementations would not hit this
bug.
JIRA: POOL-279




git-svn-id: https://svn.apache.org/repos/asf/commons/proper/pool/trunk@1647206 13f79535-47bb-0310-9956-ffa450edef68
Added JIRA reference for POOL-281.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/pool/trunk@1647211 13f79535-47bb-0310-9956-ffa450edef68
Elimiated needless if block.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/pool/trunk@1647216 13f79535-47bb-0310-9956-ffa450edef68