Indicates if auto-classes are to deleted if no activity is seen
over a given time period.
A value of 'doNotAge(1)' incicates that auto-classes are not to
be deleted based upon thier activity.
A value of 'ageOnce(2)' indicates that auto-classes which are not
active over the next xtmIfInfoAutoClassAgeTime period are to
be deleted. When read, the value of 'ageOnce(2) is returned for
approximately xtmIfInfoAutoClassAgeTime seconds, then is set by
the system back to a value of 'doNotAge(1)'.
A value of 'agePeriodically(3) indicates that auto-classes which
are not active over any xtmIfInfoAutoClassAgeTime period are to
be deleted.