LU-9727 lustre: add client NID to Changelogs entries

LU-9727 lustre: add client NID to Changelogs entries

Add a new changelog extension named changelog_ext_nid to hold
client's NID information.
NID info is added to every Changelog entry type except MARK, in
the form 'nid=<nid>':
1 01CREAT 15:50:20.834838318 2017.07.24 0x0 t=[0x200000401:0x2:0x0]
ef=0x3 u=500:500 nid=10.128.11.159@tcp p=[0x200000007:0x1:0x0] fileA

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I1049a699c17d3829d38abfade3187a28ca457bd1
Reviewed-on: https://review.whamcloud.com/28213
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Quentin Bouget <quentin.bouget@cea.fr>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>