auth_get_canonical_hostname in portable code.

"refactor canohost.c" replaced get_canonical_hostname, this makes the
same change to some portable-specific code.

auth.c

@@ -318,11 +318,12 @@ auth_log(Authctxt *authctxt, int authenticated, int partial,
 	    strncmp(method, "keyboard-interactive", 20) == 0 ||
 	    strcmp(method, "challenge-response") == 0))
 		record_failed_login(authctxt->user,
-		    get_canonical_hostname(options.use_dns), "ssh");
+		    auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
 # ifdef WITH_AIXAUTHENTICATE
 	if (authenticated)
 		sys_auth_record_login(authctxt->user,
-		    get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
+		    auth_get_canonical_hostname(ssh, options.use_dns), "ssh",
+		    &loginmsg);
 # endif
 #endif
 #ifdef SSH_AUDIT_EVENTS
@@ -653,7 +654,7 @@ getpwnamallow(const char *user)
 		    user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
 #ifdef CUSTOM_FAILED_LOGIN
 		record_failed_login(user,
-		    get_canonical_hostname(options.use_dns), "ssh");
+		    auth_get_canonical_hostname(ssh, options.use_dns), "ssh");
 #endif
 #ifdef SSH_AUDIT_EVENTS
 		audit_event(SSH_INVALID_USER);