Give camus more time to write datasets before oozie picks them up

With waiting only for the next hour's directory, we saw races where
oozie started working 3 minutes after the full hour, while camus
finished writing only 4 minutes after the full hour. This caused
erroneous reports of missing log lines.

By bumping the dependent dataset to 2 hours in the future, we grant
camus more time to finish writing the dataset.

Change-Id: Ice5444fada1609af6c6a7ba6dcdb17b57f92ea57