Comment 14 for bug 838525

Re: Thomas' comment above, as discussed in IRC, it would be better to use dob + '3 hours' (maybe 6?) instead of + '12 hours', since some patrons birth hour may be set to 12 as a way of manually avoiding the problems described in this ticket. 3 hours covers the daylight savings jitter, plus a little fudge room. Otherwise, I think this will solve the problem of some DoB's sitting just on the wrong side of the date boundary.