add yosemite to macOSXSeries
Gut the backup plugin, but keep it around for backward-compatibility.
Use the old plugin code for 1.20.
Add a deprecation warning message.
Add a TODO comment about removing the plugin.
Improve the visibility of the divider comment.
Skip new backups for 1.21 as well.
Add yosemite
Extract common method for fetching network interface id for instance
Skeleton implementation of ReleaseAddress
Skeleton (failing) test
Add upgrade step to put the system identity back.

Conflicts:
	upgrades/upgrade_test.go
Merge pull request #966 from jrwren/master

add yosemite to macOSXSeries
state: env UUID migration for meterStatus collection

This is required for multi-environment support.
missing import.
Merge pull request #1189 from mjs/meterstatus-env-uuid

state: env UUID migration for meterStatus collection

This is required for multi-environment support.

(Review request: http://reviews.vapour.ws/r/499/)
state: cleaner env config generation in EnvironSuite

A small cleanup made after discovering testing.CustomEnvironConfig().
worker/diskformatter: new worker to create filesystems

The diskformatter worker watches for block devices
assigned to datastores owned by the unit whose agent
is running the worker. Those block devices without
a filesystem will have a filesystem created, and then
recorded in state.
worker/diskmanager: fix test name
storage: add tests for BlockDevicePath

Also, remove state/datastore.go