The versions from many openstack projects don't provide the
vendor_string,product_string,version_string_with_package.
We need to keep compatible with these projects.
Closes-Bug:#1456465
Change-Id: I688ef29b84541d3261f6b9395b3f591b276aa071
(cherry-picked from oslo-incubator commit
14874b8a836b9580a94a118ed535898cfa76362f)
99a11312ed