Add a util.Forever variant that ends on a stop channel
Fixes #2681: update to cadvisor 0.6.2
Merge pull request #2683 from jimmidyson/cadvisor-0.6.2

Fixes #2681: update to cadvisor 0.6.2
Merge pull request #2661 from smarterclayton/allow_loops_to_exit

Add a util.Forever variant that ends on a stop channel
fixed bug in tools.NewEtcdClientStartServerIfNecessary