The get_all_version_data method is useful for getting a full listing of
what's going on with version discovery on a cloud. Sometimes though
people just want to see the versions for a specific service. Add a
filter to allow skipping making the version discovery call in the first
place, instead of needing to do that as a post-filtering step.
Change-Id: Ia3ca4be2976d1a5e7914fa8f2adbf7297e8cb1e1
83be7453fa