Investigate why hundreds of relays always come back at the first of a month around 00:00:00

08:57 <+GeKo> not random, always the first day of the month at about 00:00:00
08:57 <+GeKo> ah, that's the "bug", oaky
08:57 <@armacake> right. they're supposed to see how long it took them to use it 
                  all last time, and then assume they'll take the same interval 
                  this time,
08:57 <@armacake> and then randomly place that interval in the month
08:58 <@armacake> so it will likely skew early, but it should not be 00:00:00, 
                  unless it took them approximately the whole month to use it last 
                  time
09:06 <@armacake> see the file comment at the top of 
                  src/feature/hibernate/hibernate.c for how it's supposed to behave