Adds support for parsing RSA keys in the openssh-key-v1 private key format. Change-Id: Iacdcbaadf72413e4067d146203604fb50b780083 Reviewed-on: https://go-review.googlesource.com/35244 Run-TryBot: Han-Wen Nienhuys <hanwen@google.com> Reviewed-by: Paul Querna <paul@querna.org> Reviewed-by: Han-Wen Nienhuys <hanwen@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>