Fix timesync state to be uncalibrated when adjustment is large (>60ms).

Fix timesync state to be uncalibrated when adjustment is large (>60ms).

VMtools has timesync plugin to adjust guest time to match host time. Timesync
relies on a state machine (Uncalibrated, calibrating and PLL states) to
adjust the amount of guest time to match host time. If the guest and host
time differ by more than 60ms, state machine should reset to uncalibrated
state. There is a bug currently that would leave the state in PLL mode even
if the guest and host times differ by more than 60ms since absolute value of
adjustment is not considered. This causes the time sync to happen slower than
expected.