SyncManager sync blow up fix

Duplicates for periodic syncs would be
created just after boot and when a
periodic sync was delayed. This CL fixes
the behavior.

Bug: 26954967
Change-Id: I2440961629d443a62f96360563d435af9137857b
(cherry picked from commit 1675400a7cd0b56e5adc5606fb4fea77f8d24ea5)
3 files changed