DeskClock: Fix the delay or missed condition of the alarm after boot

After boot completed, if low memory condition happens or some ordered
broadcasts have time out It will cause some delay to some other ordered
broadcasts like "change_state" broadcast for alarm. Because alarm is
very sensitive to the time, its broadcast should be changed into one
with high priority. And the priority of AlarmInitReceiver should be
impoved to receive the BOOT_COMPLETE action in time. Otherwise the
alarm will be missed if AlarmInitReceiver receive the action after
the alarm time.

CRs-Fixed: 621073
Change-Id: I18f37378e5eef0504c9c412d3a2ff85487093245