When we evaluate alarms, we check the time constraints, and will check
if it is exactly match firstly, but croniter get_prev() and get_next() will
change croniter.cur time, then if it is not exactly match, the cur time is
no longer the current time, and the second call to get_prev() is not same
as first get_prev(), finally, a wrong value may returned.
For example, if start="0 11 31 * *", and current time is 2015-03-31T11:30:00,
then first get_prev() is 2015-03-31T11:00:00, but second one is 2015-05-01T11:00:00
This patch fixes it by creating a new croniter object with current time.
Change-Id: Iaeb1f763ffc33b726d132a234c8e4e08db00a8fe
Closes-Bug: #1438674
2de5cfbd8c