Placate a compiler warning introduced in r6437.

(I forgot we usually compile with -Werror on Unix, oops.)

[originally from svn r6446]
[r6437 == 8719f92c14]

ssh.c

@@ -3462,6 +3462,8 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
 		    s->tried_publickey = 0;
 		    got_passphrase = FALSE;
 		    /* and try again */
+		} else {
+		    assert(0 && "unexpected return from loadrsakey()");
 		}
 	    }