Add a util.Forever variant that ends on a stop channel
Fixes #2681: update to cadvisor 0.6.2
strip quotes in back-compat iptables
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
Handle error from watch.

A watch of the API can return an api.Status rather than the watched
obejct type.  This code didn't handle that.

Tested with services e2e test (in conjunction with other PR).
Proxy: Avoid log error.  Simplify locking.

Don't log an error when Accept failed because the interface (portal)
was just removed.

Don't pass around a pointer to a serviceInfo since another thread
deletes those.  Instead, just check if service name is still in the
service map.

Delete the locking on the serviceInfo object since it is only used
by the "main" proxier thread.
Merge pull request #2733 from erictune/handle_error

Handle error from watch.
Merge pull request #2697 from erictune/no_accept_err

Proxy: Avoid log error.  Simplify locking.
Merge pull request #2722 from thockin/iptables

strip quotes in back-compat iptables