rubygem-staypuft: Cancelling a deployment in progress by clicking on "Force unlock" doesn't work on first attempt.

Environment:
ruby193-rubygem-foreman_openstack_simplify-0.0.6-8.el7ost.noarch
openstack-foreman-installer-3.0.8-1.el7ost.noarch
ruby193-rubygem-staypuft-0.5.9-1.el7ost.noarch
rhel-osp-installer-client-0.5.4-1.el7ost.noarch
openstack-puppet-modules-2014.2.8-1.el7ost.noarch
rhel-osp-installer-0.5.4-1.el7ost.noarch


Steps to reproduce:
1. Install rhel-osp-installer.
2. Start a deployment.
3. Go to the "Overview" tab of the deployment.
4. Click on "show more details".
5. Click on "Force unlock".
6. Delete all hosts participated in the deployment.
7. Go back to the deployment.

Result:
In the majority of cases you'll see that the deployment is "paused with errors" - the progress bar is marked red.
So you'll have to click on "Force unlock" again.

Expected result:
The deployment shouldn't be paused with errors. It should state "Not deployed, yet."  - like it is after the second time I click on "Force unlock.