[Schedule] Fix bug affecting back to back scheduling.

If GetWeeklySecondDifference() was called during the second a
schedule is supposed to start, it would return a difference of
one full week instead of 0 seconds.
(cherry picked from commit 76c19a40bcd1ca8c87771646655a686f6fc16c2c)
(cherry picked from commit b3ba98b961aaabd79356b15134878f668df16cd1)
[Binaries] Commit new binary after merging b3ba98b bugfix