Do you know what happened around this time?
From your log, see the highlighted messages. There is ~3 seconds delay and the time adjusts from 10:49 to 08:49. This could also happen if the Time Zone of the Mac was changed.
18/05/15 10:49:01,727 configd[46]: network changed: v4(en0+:192.168.0.6) DNS+ Proxy+ SMB
18/05/15 10:49:01,800 com.apple.xpc.launchd[1]: (com.apple.appkit.xpc.sandboxedServiceRunner) The JoinExistingSession key is only available to Application services.
18/05/15 10:49:01,800 com.apple.xpc.launchd[1]: (com.apple.DataDetectorsDynamicData) The JoinExistingSession key is only available to Application services.
18/05/15 10:49:01,803 com.apple.xpc.launchd[1]: (com.apple.FileSyncAgent.PHD.isRunning) The HideUntilCheckIn property is an architectural performance issue. Please transition away from it.
18/05/15 10:49:01,804 com.apple.xpc.launchd[1]: (com.apple.mbloginhelper.user) This key does not do anything: OnDemand
18/05/15 10:49:01,804 com.apple.xpc.launchd[1]: (com.apple.mbpluginhost.user) This key does not do anything: OnDemand
18/05/15 10:49:01,806 com.apple.xpc.launchd[1]: (com.apple.secd) This key does not do anything: OnDemand
18/05/15 10:49:01,806 com.apple.xpc.launchd[1]: (com.apple.secd) The ServiceIPC key is no longer respected. Please remove it.
18/05/15 10:49:01,807 com.apple.xpc.launchd[1]: (com.apple.speech.speechsynthesisd) This key does not do anything: OnDemand
18/05/15 10:49:01,808 com.apple.xpc.launchd[1]: (com.apple.TrustEvaluationAgent) This key does not do anything: OnDemand
18/05/15 08:49:03,579 sntp[700]: time set -7198.599544 s
18/05/15 08:49:03,605 ntpd[340]: peer time.apple.com. @ 17.253.48.243
18/05/15 08:49:03,655 ntpd[340]: drift PPM:0.000 -> -14.815