Enable V2 pull flow

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

graph/pull.go

@@ -137,6 +137,19 @@ func (s *TagStore) CmdPull(job *engine.Job) engine.Status {
 		mirrors = s.mirrors
 	}
 
+	if isOfficial || endpoint.Version == registry.APIVersion2 {
+		j := job.Eng.Job("trust_update_base")
+		if err = j.Run(); err != nil {
+			return job.Errorf("error updating trust base graph: %s", err)
+		}
+
+		if err := s.pullV2Repository(job.Eng, r, job.Stdout, localName, remoteName, tag, sf, job.GetenvBool("parallel")); err == nil {
+			return engine.StatusOK
+		} else if err != registry.ErrDoesNotExist {
+			log.Errorf("Error from V2 registry: %s", err)
+		}
+	}
+
 	if err = s.pullRepository(r, job.Stdout, localName, remoteName, tag, sf, job.GetenvBool("parallel"), mirrors); err != nil {
 		return job.Error(err)
 	}