LU-11406 mdt: mdt_reint_setxattr() to check rr_eadata

LU-11406 mdt: mdt_reint_setxattr() to check rr_eadata

when LMV EA is requested for removal mdt_reint_setxattr() shouldn't
try to access rr_eadata as it's NULL.

Change-Id: Iae2b6a96ba72ae54a3151f86c0f53af9517e3aad
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/33273
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>