provider/null: fix storage issues

provider/null: fix storage issues

- Don't require CAKey to create a storage client
- Do not specify a default for storage-auth-key,
  and fail validation if it's not set.

A machine agent will not have an authkey initially,
as it's a secret. It is transmitted on the first
API connection. We need to fail config validation
until that point.

Fixes #1235100
Fixes #1235084

https://code.launchpad.net/~axwalk/juju-core/lp1235100-null-provider-storage/+merge/189221

(do not edit description out of merge proposal)

[axw, 2013-10-04 07:36:53]

Please take a look.

[axw, 2013-10-04 08:22:23]

Please take a look.

[fwereade, 2013-10-04 09:23:04]

Definitely needs config tests. Otherwise looking good -- the stuff in environ is
not directly testable,but you should be able to verify that you can't create an
environ without the fields you need.

https://codereview.appspot.com/14387043/diff/4001/provider/null/config.go
File provider/null/config.go (right):

https://codereview.appspot.com/14387043/diff/4001/provider/null/config.go#new...
provider/null/config.go:25: "storage-auth-key":  schema.String(),
Needs a test that this fails verification if missing.

[axw1, 2013-10-04 09:36:55]

https://codereview.appspot.com/14387043/diff/4001/provider/null/config.go
File provider/null/config.go (right):

https://codereview.appspot.com/14387043/diff/4001/provider/null/config.go#new...
provider/null/config.go:25: "storage-auth-key":  schema.String(),
On 2013/10/04 09:23:04, fwereade wrote:
> Needs a test that this fails verification if missing.

Done, and actually this line should just be deleted (we don't want a default,
and we certainly don't want a default of schema.String() ;))

[axw, 2013-10-04 09:38:23]

Please take a look.

[fwereade, 2013-10-04 09:40:00]

LGTM pending live verification

[axw, 2013-10-04 09:49:18]

Please take a look.

[rog, 2013-10-04 09:55:06]

LGTM with one possible thought

https://codereview.appspot.com/14387043/diff/15001/provider/null/environ.go
File provider/null/environ.go (right):

https://codereview.appspot.com/14387043/diff/15001/provider/null/environ.go#n...
provider/null/environ.go:178: logger.Errorf("missing CA cert or auth-key")
This could actually be a panic, I think, as we shouldn't be able to get to this
stage without both of those things set.