x/crypto/ssh: add ed25519 certs to supportedHostKeyAlgos

Change-Id: I46bb7721c081b8a9b0395a4f7c49b7f3e27bbc49
Reviewed-on: https://go-review.googlesource.com/24831
Reviewed-by: Adam Langley <agl@golang.org>

ssh/common.go

@@ -44,7 +44,7 @@ var supportedKexAlgos = []string{
 // of authenticating servers) in preference order.
 var supportedHostKeyAlgos = []string{
 	CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01,
-	CertAlgoECDSA384v01, CertAlgoECDSA521v01,
+	CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01,
 
 	KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
 	KeyAlgoRSA, KeyAlgoDSA,