spaces constraints should fail if you use an unknown space name

[John A Meinel]

If I do:

 juju add-machine lxd:0 --constraints space=BLAH

And "BLAH" isn't a known space, the add-machine request goes through, but the machine never gets provisioned. And thanks to bug #1650252, the container just shows up as 'pending' forever.

We should reject spaces that we don't know when we parse the constraint. That way you get rejected immediately instead of having a machine that we will never be able to provision.

I assume this is also true without LXD (juju add-machine --constraints spaces=BLAH), but I didn't test that.

[John A Meinel (jameinel)]

It appears that "--bind blah" does validate that 'blah' is a known space, but "--constraints spaces=blah" is not validated.

[Heather Lanigan (hmlanigan)]

The spaces constraint values are now validated, not sure at what version.

$ juju add-machine lxd --constraints spaces=BLAH
ERROR bad "spaces" constraint: "BLAH" is not a valid space name