ssh: make client auth tests less chatty.
ssh: make client auth tests less chatty.

Change-Id: Ib35ce0e7437e32a3fa24a9330c479306b7fa6880
Reviewed-on: https://go-review.googlesource.com/35011
Reviewed-by: Adam Langley <db68fba232b2c49ed3e9d3081df349dde7b61dfd@golang.org>

ScriptRock/crypto,golang/crypto,ScriptRock/crypto,golang/crypto,golang/crypto