LU-9771 flr: resync support and test tool

LU-9771 flr: resync support and test tool

A tool to resync mirrored file after writing.
It extends the Lustre lease API to support taking file lease and then
sending the MDS_REINT_RESYNC RPC to the MDT so that it can increase
the file's layout version; then the client will start copying
the contents from valid mirror to stale mirrors. At the end of
resync, the copying client will release the lease and revalidate
stale mirrors.

Test-Parameters: testlist=sanity-flr
Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Change-Id: I59f84cd501f6945225c97bdb99a142ae7efbf0fb
Reviewed-on: https://review.whamcloud.com/29096
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>