The patch https://review.openstack.org/#/c/357555/ is already available in latest OSP10 puddle.
http://download-node-02.eng.bos.redhat.com/rcm-guest/puddles/OpenStack/10.0-RHEL-7/2018-04-02.1/
[root@overcloud-controller-0 heat-admin]# yum info python-os-vif.noarch
Loaded plugins: product-id, search-disabled-repos, subscription-manager
This system is not registered with an entitlement server. You can use subscription-manager to register.
Installed Packages
Name : python-os-vif
Arch : noarch
Version : 1.2.1
Release : 3.el7ost
Size : 182 k
Repo : installed
From repo : rhos-10.0-signed
Summary : OpenStack os-vif library
URL : http://launchpad.net/os-vif/
License : ASL 2.0
Description : A library for plugging and unplugging virtual interfaces in OpenStack.