'"' has special semantic meaning that conflicts with using it as Comma.

Change-Id: Ife25ba43ca25dba2ea184c1bb7579a230d376059
Reviewed-on: https://go-review.googlesource.com/99696
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>