Tests/Undo/TestUndoStackTrackProtocol.m: Raise maximum delay since undo node commit date to avoid spurious test failure on Travis

git-svn-id: svn://svn.gna.org/svn/etoile/trunk/Etoile/Frameworks/CoreObject@9833 7b3f36aa-e6db-49c1-8b4c-66eac1997e64