ssh/terminal: consistent return value for Restore
ssh/terminal: consistent return value for Restore

This patch makes the Restore function return nil
on success to be consistent with other functions
like MakeRaw.

Change-Id: I81e63f568787dd88466a5bb30cb87c4c3be75a5c
Reviewed-on: https://go-review.googlesource.com/34952
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

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