Also add missing switch cases which cause a compiler warning on OS X. They are unused so far. Fixes golang/go#16071 Change-Id: I5ced5a814a7abc956b0b0cdad211ecd69a54a95b Reviewed-on: https://go-review.googlesource.com/24177 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>