Code review comment for lp:~wallyworld/juju-core/provisioner-api-supported-containers

Reviewers: mp+194982_code.launchpad.net,

Message:
Please take a look.

Description:
AddSupportedContainers on provisioner machine api

The AddSupportedContainers api on the provisioner.Machine
will be used by future changes to machine agent initialisation.

A change was also made to the server side implementation so that
the machine doc txn-revno is no longer checked. It was causing issues
with multi-threaded tests where different fields in the machine doc
were being updated. The machine agent initialisation thread is the
only one that updates the supported containers set.

https://code.launchpad.net/~wallyworld/juju-core/provisioner-api-supported-containers/+merge/194982

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/25480047/

Affected files (+113, -4 lines):
   A [revision details]
   M state/api/params/internal.go
   M state/api/provisioner/machine.go
   M state/api/provisioner/provisioner_test.go
   M state/apiserver/provisioner/provisioner.go
   M state/apiserver/provisioner/provisioner_test.go
   M state/machine.go