if we give multiple options/ranges for a value, e.g.
2,4,8
we always choose the biggest, instead of the smallest that is next
this happens because in DateTimeValue::find_next(value)
'next' can be set multiple times and we set it when the new
value was *bigger* than the last found 'next' value, when in reality
we have to choose the *smallest* next we can find
reverse the comparison operator to fix this
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>