Changed warning display for unknown config, remove tools-url on upgrade, added/modified tests. Bug 1383070.
Clarify comment. Bug 1383070.
Test cleanup as per review. Bug 1383070.
Allow env-set to handle deprecated attributes
Tweak test
Replace loopback url (localhost, etc) with network bridge ip. Bug 1309207.
Merge pull request #1016 from wallyworld/deprecated-set-env

Allow env-set to handle deprecated attributes

Fixes: https://bugs.launchpad.net/bugs/1387953

Customers will not be hitting this issue but the CI scripts do because they set tools-metadata-url during the course of CI testing.

When set-env is used, you can now pass in deprecated attributes and they will be converted to the new values. The code used to initially parse env config is shared.

As a drive by, convert some more config string literals to constants.
Write metadata for ppc64; do not write product metadata if it has not changed
upgrades: run upgrade steps for final release when upgrading to an alpha or beta release

This allows definition and testing of upgrade steps as we work towards
a stable release.
upgrades: target 1.21 steps at 1.21 final, not alpha1

Targeting at alpha1 was just a temporary step until the upgrade step
selection logic was changed. Also added a check to ensure that upgrade
steps are only targeted to final releases.
cmd/jujud: test fix due to changed upgrade steps selection logic
Small tweak
Refactor metadataUnchanged to be clearer
Explicitly pass in the streams for which to write metadata
state: strictLocalID tweaks

1. Return an error instead of a flag to reduce boilerplate at call
sites.

2. Use strictLocalID in more places where appropriate.
Merge pull request #1021 from wallyworld/simplestreams-ppc64

Write metadata for ppc64; do not write product metadata if it has not changed

Fixes: https://bugs.launchpad.net/juju-core/+bug/1388493

This PR does 2 things:

1. If tools for ppc64el are found, metadata is also generated for ppc64 so that older versions of Juju which look for ppc64 can find tools.

2. When writing simplestreams product metadata for tools, if the generated metadata is the same as what's there, do not overwrite the file.
Replace loopback url (localhost, etc) with network bridge ip. Bug 1309207.
Merge remote-tracking branch 'origin/replace-localhost-in-proxies' into replace-localhost-in-proxies

Conflicts:
	environs/config/config.go
Resolving merge conflict.
Merge pull request #1010 from mjs/upgrade-steps-selection

Tweak upgrade steps selection logic and retarget 1.21 upgrade steps

upgrades: run upgrade steps for final release when upgrading to an alpha or beta release

This allows definition and testing of upgrade steps as we work towards a stable release.

---

upgrades: target 1.21 steps at 1.21 final, not alpha1

Targeting at alpha1 was just a temporary step until the upgrade step selection logic was changed. Also added a check to ensure that upgrade steps are only targeted to final releases.