Related 1.19 issue https://projects.theforeman.org/issues/23818

A fix for this has already been merged to 1.18 - https://github.com/theforeman/foreman/commit/1a191e14e4485c304ec37e519cce9c2d398a37b5 - https://github.com/theforeman/foreman-packaging/commit/ef263ced3e2ed8b7b541f02600bea40c8a3ec7a8

Could you share which version of fog-openstack are you using?

I'm seeing the same issue with a generic Pike OpenStack. I installed Foreman/Katello via https://theforeman.org/plugins/katello/3.7/installation/index.html. After setting up the yum repos, I did:

foreman-installer --scenario katello
foreman-installer --enable-foreman-compute-openstack
systemctl restart foreman-proxy.service

fog-openstack and foreman-openstack versions:

[centos@foreman-server-bsq6q6gd2hmt ~]$ rpm -qa | grep -i openstack
tfm-rubygem-fog-openstack-0.1.25-1.el7.noarch
foreman-openstack-1.18.1-1.el7.noarch

[centos@foreman-server-bsq6q6gd2hmt ~]$ rpm -qi tfm-rubygem-fog-openstack-0.1.25-1.el7.noarch
Name        : tfm-rubygem-fog-openstack
Version     : 0.1.25
Release     : 1.el7
Architecture: noarch
Install Date: Wed 29 Aug 2018 12:15:04 AM UTC
Group       : Development/Ruby
Size        : 1146914
License     : MIT
Signature   : RSA/SHA1, Fri 22 Jun 2018 12:45:34 PM UTC, Key ID 4c3dd0b357cef41f
Source RPM  : tfm-rubygem-fog-openstack-0.1.25-1.el7.src.rpm
Build Date  : Fri 08 Jun 2018 02:55:10 PM UTC
Build Host  : koji.katello.org
Relocations : (not relocatable)
Packager    : Koji
Vendor      : Koji
URL         : https://github.com/fog/fog-openstack
Summary     : Module for the 'fog' gem to support OpenStack clouds
Description :
This is the plugin Gem to talk to OpenStack clouds via fog.

[centos@foreman-server-bsq6q6gd2hmt ~]$ rpm -qi foreman-openstack-1.18.1-1.el7.noarch
Name        : foreman-openstack
Version     : 1.18.1
Release     : 1.el7
Architecture: noarch
Install Date: Wed 29 Aug 2018 12:33:57 AM UTC
Group       : Applications/System
Size        : 68
License     : GPLv3+ with exceptions
Signature   : RSA/SHA1, Thu 16 Aug 2018 06:22:16 AM UTC, Key ID 4c3dd0b357cef41f
Source RPM  : foreman-1.18.1-1.el7.src.rpm
Build Date  : Wed 15 Aug 2018 11:59:37 AM UTC
Build Host  : koji.katello.org
Relocations : (not relocatable)
Packager    : Koji
Vendor      : Koji
URL         : https://theforeman.org
Summary     : Foreman OpenStack support
Description :
Meta package to install requirements for OpenStack compute resource support.