This was resolved by openstack-cinder-2015.1.2-5.el7ost, available from the OpenStack 7 repository.

The current permissions are:

%dir %attr(0750, cinder, cinder) %{_localstatedir}/log/cinder

(In reply to Lon Hohberger from comment #3)
> This was resolved by openstack-cinder-2015.1.2-5.el7ost, available from the
> OpenStack 7 repository.
> 
> The current permissions are:
> 
> %dir %attr(0750, cinder, cinder) %{_localstatedir}/log/cinder

That doesn't seem to be the case:

%dir %attr(0750, cinder, root) %{_localstatedir}/log/cinder
...
%changelog
* Fri Dec 04 2015 Eric Harney <eharney> 2015.1.2-5
- Revert Filter-snapshots-data-on-the-DB-side (RHBZ #1287621)

* Thu Dec 03 2015 Jon Bernard <jobernar> 2015.1.2-4
...

# ll -d /var/log/{keystone,nova,neutron,cinder,glance}
drwxr-x---. 2 cinder   root       98 Apr 13 09:51 /var/log/cinder
drwxr-x---. 2 glance   glance     39 Apr 13 09:49 /var/log/glance
drwxr-x---. 2 keystone keystone   25 Apr 13 09:44 /var/log/keystone
drwxr-x---. 2 neutron  neutron  4096 Apr 13 10:18 /var/log/neutron
drwxr-x---. 2 nova     nova     4096 Apr 14 03:14 /var/log/nova
# rpm -q openstack-cinder 
openstack-cinder-2015.1.2-5.el7ost.noarch

Any ideas?

I might add that -5 is the latest available release in the OSP 7 repo:

# yumdownloader --url openstack-cinder
Loaded plugins: product-id
https://cdn.redhat.com/content/dist/rhel/server/7/7Server/x86_64/openstack/7.0/os/Packages/openstack-cinder-2015.1.2-5.el7ost.noarch.rpm

OK, a newer version, openstack-cinder-2015.1.3-5.el7ost, has been released.