imapc: Make sure storage error has the proper auth failure error string

The first failed command always had the correct error string, but the
following failed commands just returned -1 without updating storage error.
The storage error could have been something completely different by then.

src/lib-storage/index/imapc/imapc-storage.c

@@ -231,28 +231,36 @@ imapc_storage_client_login_callback(const struct imapc_command_reply *reply,
 
 	client->auth_failed_state = reply->state;
 	client->auth_failed_reason = i_strdup(reply->text_full);
+	if (!imapc_storage_client_handle_auth_failure(client))
+		i_unreached();
+}
+
+bool imapc_storage_client_handle_auth_failure(struct imapc_storage_client *client)
+{
+	if (client->auth_failed_state == IMAPC_COMMAND_STATE_OK)
+		return FALSE;
 
+	/* We need to set the error to either storage or to list, depending on
+	   whether the caller is from mail-storage.h API or mailbox-list.h API.
+	   We don't know here what the caller is though, so just set the error
+	   to both of them. */
 	if (client->_storage != NULL) {
-		if (reply->state == IMAPC_COMMAND_STATE_DISCONNECTED)
+		if (client->auth_failed_state == IMAPC_COMMAND_STATE_DISCONNECTED)
 			mail_storage_set_internal_error(&client->_storage->storage);
 		else {
 			mail_storage_set_error(&client->_storage->storage,
-					       MAIL_ERROR_PERM, reply->text_full);
+				MAIL_ERROR_PERM, client->auth_failed_reason);
 		}
 	}
 	if (client->_list != NULL) {
-		if (reply->state == IMAPC_COMMAND_STATE_DISCONNECTED)
+		if (client->auth_failed_state == IMAPC_COMMAND_STATE_DISCONNECTED)
 			mailbox_list_set_internal_error(&client->_list->list);
 		else {
 			mailbox_list_set_error(&client->_list->list,
-					       MAIL_ERROR_PERM, reply->text_full);
+				MAIL_ERROR_PERM, client->auth_failed_reason);
 		}
 	}
-}
-
-bool imapc_storage_client_handle_auth_failure(struct imapc_storage_client *client)
-{
-	return client->auth_failed_state != IMAPC_COMMAND_STATE_OK;
+	return TRUE;
 }
 
 static void imapc_storage_client_login(struct imapc_storage_client *client,