private Map<String, ManifestService> buildManifestByService() {
    Map<String, ManifestService> manifests = new HashMap<>();

    for (ManifestService manifest : manifestServices) {
      if (!manifests.containsKey(manifest.serviceName)) {
        manifests.put(manifest.serviceName, manifest);
      }
    }

    return manifests;
  }
Structures the manifest by service name.
<p/>
!!! WARNING. This is currently based on the assumption that there is one and only
one version for a service in the VDF.  This may have to change in the future.
</p>
@return
ambari-server/src/main/java/org/apache/ambari/server/state/repository/VersionDefinitionXml.java