disable apsd on buildbot build slaves

[ryandesign (Ryan Carsten Schmidt)]

On the tennine-slave and tenten-slave buildbot builders, apsd (the Apple Push Notification service daemon, part of iMessage) eats up CPU and spams the system log with messages like:

apsd: Hardware SerialNumber "VMW......." looks incorrect or invalid

In this case, the invalid serial numbers are the ones generated by VMware for these virtual machines. Other users running OS X in virtualization report the same problem.

apsd also runs on the teneight-slave builder. It doesn't generate these errors there, but does generate less frequent error messages like:

apsd[201]: Couldn't find cert in response dict
apsd[201]: Failed to get client cert on attempt 7462, will retry in 900 seconds

apsd is not running on tensix-slave or tenseven-slave.

We don't care about iMessage on the buildbot build slaves so we should disable this to save CPU time and disk space.

[ryandesign (Ryan Carsten Schmidt)]

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.apsd.plist

[ryandesign (Ryan Carsten Schmidt)]

I ran this command on the new 10.8, 10.9, and 10.10 workers. I need to do it on the new 10.11 and 10.12 workers too, but I need to reboot them with SIP disabled before I can do that.