LU-9538 utils: Tool for syncing file LSOM xattr

LU-9538 utils: Tool for syncing file LSOM xattr

Add a helper tool for syncing file LSOM xattr.
Firstly, register a new changelog user:
lctl --device lustre-MDT0000 changelog_register

After perform some file operations on Lustre file system, run
this tool to sync file LSOM xattr:
llsom_sync -u cl1 -m lustre-MDT0000 /mnt/lustre

Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: Ia2878b48f7f665b01b230585921c78ae41846171
Reviewed-on: https://review.whamcloud.com/30124
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>