Merge pull request #491 from iamqizhao/master

Finish tracing when failing to create a client stream
diff --git a/stream.go b/stream.go
index 537d4b3..3ac5f6a 100644
--- a/stream.go
+++ b/stream.go
@@ -125,6 +125,7 @@
 	}
 	s, err := t.NewStream(ctx, callHdr)
 	if err != nil {
+		cs.finish(err)
 		return nil, toRPCErr(err)
 	}
 	cs.t = t