Chris Walker reports a silly typo in HTML reporting: the < and > signs

used in the mouseover text for file ages outside the colour range were
the wrong way round! I must have been thinking about comparison of
time_ts, in which case < does mean older, but by the time I print the
output it's in the form of an age, so > means older.

git-svn-id: svn://svn.tartarus.org/sgt/agedu@9415 cda61777-01e9-0310-a592-d414129be87e