Show correct remaining time

In field reports, sometimes the remaining time gets stuck for many
minutes. This has to be caused by a spurious low reading early on which
cannot be overridded because of old logic.

Solution: allow time to increase but only by large amounts (avoid time
jittering up and down).

Bug: 16973374
Change-Id: I49d23ae8c54ded416cbedf383a3c03b33dc02e1c
1 file changed