Don't force a due date on unscheduled milestones.  Refs #9566.
Don't force a due date on unscheduled milestones.  Refs #9566.

An unscheduled milestone no longer defaults to being due today but gets
its date from the scheduler.

git-svn-id: 2159781fc7c14c6bdd1f7e265daf7a25099c31e7@11153 7322e99d-02ea-0310-aa39-e9a107903beb

trac-hacks/trac-jsGantt,trac-hacks/trac-jsGantt,trac-hacks/trac-jsGantt