Milo: Don't float step times if build has finished

milo/appengine/buildbot/builder.go

Index: milo/appengine/buildbot/builder.go
diff --git a/milo/appengine/buildbot/builder.go b/milo/appengine/buildbot/builder.go
index 6a9cd265fdad82c6a6a0727b1d372fb67d607434..8bb9be08e902d1099f4d44a3509e81e135302115 100644
--- a/milo/appengine/buildbot/builder.go
+++ b/milo/appengine/buildbot/builder.go
@@ -64,7 +64,7 @@ func mergeText(text []string) []string {
 }
 
 func getBuildSummary(b *buildbotBuild) *resp.BuildSummary {
-	started, finished, duration := parseTimes(b.Times)
+	started, finished, duration := parseTimes(nil, b.Times)
 	return &resp.BuildSummary{
 		Link: &resp.Link{
 			URL:   fmt.Sprintf("%d", b.Number),