Another bustage fix for signing servers.
Merge bustage fix.

--HG--
branch : production
Bug 1052192: use /usr/local/bin/hg for puppetmasters; r=dividehex
Bug 1050513: disable ReportPanicService where it exists; r=bhearsum
Bug 1050513: enforce administrator account (with root pw) on Mavericks; r=bhearsum
Bug 1050513: depend on Darwinuser for old OS X and User for new; r=bhearsum
Bug 1050513: require collectd be installed before starting service; r=bhearsum
Bug 1050513: actually start the puppet service; r=bhearsum
Merge default -> production

--HG--
branch : production
Bug 1032391 - update unzip on mac os x build/test machines to 6.0 - with ubuntu fix, r=dustin
merges default -> production

--HG--
branch : production
Bug 942468: correct landing of qa-config.pp; r=Callek
Merge default -> production

--HG--
branch : production
Bug 1046926: run instance_metadata as a runner task on CentOS; r=ianconnolly
Merge default -> production

--HG--
branch : production
bug 1049595: cope with signing server transition in buildbot configs. r=rail
Merge from default.

--HG--
branch : production
Bug 1046926: only set instance_metadata on releng slaves; r=coop
Merge default -> production

--HG--
branch : production
Bug 1051558: whack Apple's ntpd hourly to keep it working; r=bhearsum