Same here.  Slave did not reboot at end of build.

2017-06-21 18:29:20-0700 [-] command finished with signal None, exit code 0, elapsedTime: 12234.871535
2017-06-21 18:29:20-0700 [-] SlaveBuilder.commandComplete <buildslave.commands.shell.SlaveShellCommand instance at 0x7f35c04cef80>
2017-06-21 18:29:21-0700 [-] sending app-level keepalive
2017-06-21 18:29:31-0700 [Broker,client] Setting needs_reboot flag
2017-06-21 18:29:31-0700 [Broker,client] slave shutting down on command from master
2017-06-21 18:29:31-0700 [-] firing system event shutdown
2017-06-21 18:29:31-0700 [-] calling before trigger: <bound method MultiService.stopService of <twisted.application.service.MultiService instance at 0x7f35c04ce290>>
2017-06-21 18:29:31-0700 [-] stopping service <buildslave.bot.BuildSlave instance at 0x7f35c04ce170>
2017-06-21 18:29:31-0700 [-] stopping service <twisted.application.internet.TCPClient instance at 0x7f35c04ce248>
2017-06-21 18:29:31-0700 [-] stopped service <twisted.application.internet.TCPClient instance at 0x7f35c04ce248>
2017-06-21 18:29:31-0700 [-] stopping service <buildslave.bot.Bot instance at 0x7f35c04ce830>
2017-06-21 18:29:31-0700 [-] stopping service <SlaveBuilder 'android_nexus5_perf_bisect' at 139868835976256>
2017-06-21 18:29:31-0700 [-] stopped service <SlaveBuilder 'android_nexus5_perf_bisect' at 139868835976256>
2017-06-21 18:29:31-0700 [-] stopped service <buildslave.bot.Bot instance at 0x7f35c04ce830>
2017-06-21 18:29:31-0700 [-] stopped service <buildslave.bot.BuildSlave instance at 0x7f35c04ce170>
2017-06-21 18:29:31-0700 [-] calling during/after trigger: <bound method SelectReactor.crash of <twisted.internet.selectreactor.SelectReactor object at 0x7f35bffd9990>>
2017-06-21 18:29:31-0700 [-] calling during/after trigger: <bound method SelectReactor.disconnectAll of <twisted.internet.selectreactor.SelectReactor object at 0x7f35bffd9990>>
2017-06-21 18:29:31-0700 [Broker,client] lost remote
2017-06-21 18:29:31-0700 [Broker,client] Lost connection to master4.golo.chromium.org:8141
2017-06-21 18:29:31-0700 [Broker,client] Stopping factory <buildslave.bot.BotFactory instance at 0x7f35c04ce878>
2017-06-21 18:29:31-0700 [-] calling during/after trigger: <function stop_timeseries_monitoring at 0x7f35c2713500>
2017-06-21 18:29:31-0700 [-] calling during/after trigger: <bound method SelectReactor._stopThreadPool of <twisted.internet.selectreactor.SelectReactor object at 0x7f35bffd9990>>
2017-06-21 18:29:31-0700 [-] finished firing system event
2017-06-21 18:29:31-0700 [-] Main loop terminated.
2017-06-21 18:29:31-0700 [-] Server Shut Down.