LU-17010 lfsck: don't create trans in dryrun mode

LU-17010 lfsck: don't create trans in dryrun mode

In LFSCK, the LFSCK transaction should not be created in
dryrun mode, which is related to the following patch,

Fixes: 0c1ae1cb9c19 ("LU-13124 scrub: check for multiple linked file")
Change-Id: Id543bc3c0e300c1cc14b670d724ebcacac3bf71b
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/51849
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>