LU-11226 flr: mirror resync regression

LU-11226 flr: mirror resync regression

There is a glitch in the lfs mirror resync tool in commit
0e5c12ac29a9622e8ca05d5e39cd5e2a721ace93, resync write needs to
restricted to the component's extent.

Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Change-Id: Ifbd3f16b2f621407b31c7fe37ce9745de48fcc99
Reviewed-on: https://review.whamcloud.com/32968
Tested-by: Jenkins
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>