LU-10375 ptlrpc: fix error handling after tx creation

LU-10375 ptlrpc: fix error handling after tx creation

we don't need to stop a transaction if it wasn't created
(i.e. if dt_trans_create() returned an error).

Fixes: 928714ddda ("LU-5092 nodemap: save id maps to targets in new index file")

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I04a707ab068ff1278c891cd1c7646ec37cac0055
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/57583
Tested-by: Maloo <maloo@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>