Code review comment for lp:~thumper/juju-core/common-api-env-watcher

Reviewers: mp+202766_code.launchpad.net,

Message:
Please take a look.

Description:
Refactor client side api to have common behaviour

The apiserver components have a common packge that
enables other end points to share the implementation
of some common facilities.

The api client side should also have this common
behaviour.

This branch starts this with the environ watcher
and getter for the provisioner. This will be used
by the Uniter in the next branch.

In order to reduce import cycles the common.Caller
interface had to be moved. It was either that or to
have the common code in a different package. I
decided that it was better to have the same package
name for the common code on both the client and
server side for the api, so common.Caller becomes
base.Caller.

https://code.launchpad.net/~thumper/juju-core/common-api-env-watcher/+merge/202766

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/52610045/

Affected files (+104, -75 lines):
   A [revision details]
   M state/api/agent/state.go
   M state/api/base/caller.go
   M state/api/charmrevisionupdater/updater.go
   A state/api/common/environwatcher.go
   M state/api/deployer/deployer.go
   M state/api/keyupdater/authorisedkeys.go
   M state/api/logger/logger.go
   M state/api/machiner/machiner.go
   M state/api/provisioner/provisioner.go
   M state/api/uniter/uniter.go
   M state/api/upgrader/upgrader.go
   M state/api/watcher/watcher.go