genfio: Fixing empty ETA while runtime > 0

Commit 920e0b66756814f7d01bcbbaf5cf0fd05213628d introduced the runtime=0
support but did considered the amount of minutes in addition of rounded
hours to consider if the ETA message can be shown or not.

This is perfectly wrong since it should have been the total amount of
seconds to consider. If runtime=0, the amount of seconds to run cannot
be computed as = 0.

The present code was wrong as if runtime was rounded on hours it did
show the message that ETA cannot be computed.