ssh: fix call to Fatalf from a non-test goroutine

Also fix some redundant type declarations.

Change-Id: Iad2950b67b1ec2e2590c59393b8ad15421ed3add
GitHub-Last-Rev: 41cf552f11387208491dee7b867050475043b25e
GitHub-Pull-Request: golang/crypto#263
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/505798
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>

ssh/benchmark_test.go

@@ -6,6 +6,7 @@ package ssh
 
 import (
 	"errors"
+	"fmt"
 	"io"
 	"net"
 	"testing"
@@ -90,16 +91,16 @@ func BenchmarkEndToEnd(b *testing.B) {
 	go func() {
 		newCh, err := server.Accept()
 		if err != nil {
-			b.Fatalf("Client: %v", err)
+			panic(fmt.Sprintf("Client: %v", err))
 		}
 		ch, incoming, err := newCh.Accept()
 		if err != nil {
-			b.Fatalf("Accept: %v", err)
+			panic(fmt.Sprintf("Accept: %v", err))
 		}
 		go DiscardRequests(incoming)
 		for i := 0; i < b.N; i++ {
 			if _, err := io.ReadFull(ch, output); err != nil {
-				b.Fatalf("ReadFull: %v", err)
+				panic(fmt.Sprintf("ReadFull: %v", err))
 			}
 		}
 		ch.Close()