LU-17250 mgs: fix resource leak in name_create_osp

LU-17250 mgs: fix resource leak in name_create_osp

This patch fixes a resource leak detected by Coverity:

CID 425355:    (RESOURCE_LEAK)
/lustre/mgs/mgs_llog.c: 189 in name_create_osp()

Fixes: d4682ff ("LU-17250 mgs: generate a new MDT configuration by copy")
Signed-off-by: Etienne AUJAMES <eaujames@ddn.com>
Change-Id: I8e0cbc3507e5a9882b2cfadfd68aea318575fc7a
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55238
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>