git-review: add -q to git branch --set-upstream-to command

Git is currently spamming me with:

$ git change upstreamq
Branch upstreamq set up to track remote branch master from origin.
git-review: created branch upstreamq tracking origin/master.
$

I introduced this by submitting my other change earlier this morning.

TBR=adg

Change-Id: I68a96d68541d211bda546ed490085632982bc905
Reviewed-on: https://go-review.googlesource.com/1430
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/git-review/change.go b/git-review/change.go
index 4414f37..9e5f1d5 100644
--- a/git-review/change.go
+++ b/git-review/change.go
@@ -102,6 +102,6 @@
 
 	// NOTE: This is different from git checkout -q -t -b branch. It does not move HEAD.
 	run("git", "checkout", "-q", "-b", target)
-	run("git", "branch", "--set-upstream-to", origin)
+	run("git", "branch", "-q", "--set-upstream-to", origin)
 	printf("created branch %v tracking %s.", target, origin)
 }
diff --git a/git-review/change_test.go b/git-review/change_test.go
index 811a684..f493d94 100644
--- a/git-review/change_test.go
+++ b/git-review/change_test.go
@@ -18,7 +18,7 @@
 	t.Logf("master -> work")
 	testMain(t, "change", "work")
 	testRan(t, "git checkout -q -b work",
-		"git branch --set-upstream-to origin/master",
+		"git branch -q --set-upstream-to origin/master",
 		"git commit -q --allow-empty -m my commit msg")
 
 	t.Logf("work -> master")