Ivy now requires Java 5

git-svn-id: https://svn.apache.org/repos/asf/ant/ivy/core/trunk@1577709 13f79535-47bb-0310-9956-ffa450edef68
Merged r1577709 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/ant/ivy/core/branches/2.4.x@1577719 13f79535-47bb-0310-9956-ffa450edef68