Create volume snapshot action should check quotas

[Kieran Spear]

Currently there's no quota check when creating a snapshot from a volume. We should do something similar to the CreateVolume action, which disables the button if the action is bound to fail due to quota.

The relevant cinder quotas are:

snapshots
gigabytes (if cinder is configured to include snapshot size in overall gigabytes quota)

[Mike Perez (thingee)]

Spoke with Romain before grabbing this.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/75442

[Mike Perez (thingee)]

I'm not sure if this is needed anymore. I just noticed the button is hidden if you're already over quota. If someone did something sneaky, I wouldn't care if they got a generic error.

[Justin Pomeroy (jpomero)]

As noted above, I don't think this is an issue anymore. The cinder limits are being checked to determine if the maxTotalSnapshots has been reached. It doesn't look like there is a check for total gigabyte usage though, so it's possible that should still be added, if there is even a way to determine if cinder is configured to include snapshot size in overall gigabytes quota.