Code review comment for lp:~fwereade/pyjuju/env-constraints

Reviewers: mp+99852_code.launchpad.net,

Message:
Please take a look.

Description:
Implement environment constraints

In user-visible terms:

* bootstrap now accepts --constraints;
* set-constraints now works without --service;
* get-constraints now accepts empty args and outputs env constraints.

In developer terms:

* EnvironmentStateManager has new methods for get/set constraints;
* A new /constraints node is used to store environment constraints (if
you
   can think of a better way to do this, bearing in mind that we can't
create
   /environment until we've got data for the PA in there, please tell
me);
* MachineProvider.bootstrap now requires a Constraints;
* CloudInit now needs a Constraints when setting up a master;
* juju-admin initialize now accept --constraints-data;
* get-constraints and set-constraints take an apparent long way round to
   construct their constraints (they sync environents.yaml so that a
provider
   can be created from it by EnvironmentStateManager -- but ESM is used
   internally in a number of places, and the fact that we have a provider
   already available at the juju.control level is not so helpful);
* an awful lot of the diff is tedious test fixing in juju.providers.

https://code.launchpad.net/~fwereade/juju/env-constraints/+merge/99852

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/5957043/

Affected files:
   A [revision details]
   M juju/agents/tests/test_provision.py
   M juju/control/bootstrap.py
   M juju/control/constraints_get.py
   M juju/control/constraints_set.py
   M juju/control/deploy.py
   M juju/control/initialize.py
   M juju/control/tests/test_add_unit.py
   M juju/control/tests/test_bootstrap.py
   M juju/control/tests/test_constraints_get.py
   M juju/control/tests/test_constraints_set.py
   M juju/control/tests/test_deploy.py
   M juju/control/tests/test_initialize.py
   M juju/control/utils.py
   M juju/environment/tests/test_config.py
   M juju/providers/common/base.py
   M juju/providers/common/bootstrap.py
   M juju/providers/common/cloudinit.py
   M juju/providers/common/launch.py
   M juju/providers/common/tests/data/cloud_init_bootstrap
   M juju/providers/common/tests/data/cloud_init_bootstrap_zookeepers
   M juju/providers/common/tests/data/cloud_init_distro
   M juju/providers/common/tests/data/cloud_init_ppa
   M juju/providers/common/tests/test_bootstrap.py
   M juju/providers/common/tests/test_cloudinit.py
   M juju/providers/dummy.py
   M juju/providers/ec2/tests/common.py
   M juju/providers/ec2/tests/data/bootstrap_cloud_init
   M juju/providers/ec2/tests/test_bootstrap.py
   M juju/providers/local/__init__.py
   M juju/providers/local/tests/test_provider.py
   M juju/providers/orchestra/tests/data/bootstrap_user_data
   M juju/providers/orchestra/tests/test_bootstrap.py
   M juju/providers/tests/test_dummy.py
   M juju/state/environment.py
   M juju/state/initialize.py
   M juju/state/machine.py
   M juju/state/service.py
   M juju/state/tests/test_environment.py
   M juju/state/tests/test_initialize.py
   M juju/state/tests/test_service.py