[cinder][grenade][neutron] Gate failure in grenade jons

Hi Cinder team,

I saw in Neutron CI in last few days that all our grenade jobs (multinode if that is important) are failing with error which seems to be related to Cinder. I opened bug [1] for that. Please take a look at it as it seems pretty serious issue because our gate is now broken because of that. Sorry if there is already another bug reported for the same problem and I created duplicate :) If bug is somehow hard to fix or there is nobody who can take a look, I will be also greatful for such info so we can temporary mark those grenade jobs as non-voting to unblock our gate :)

Thx a lot in advance for Your help.

[1] https://bugs.launchpad.net/cinder/+bug/1901384