LU-7186 lod: do not propagate size if stripeless

LU-7186 lod: do not propagate size if stripeless

if a file has no stripes, but the size isn't zero,
then do not try to propagate this size to stripes.

Change-Id: I25401bcc41e3ea84a2b9158120f1e907af47fafa
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-on: http://review.whamcloud.com/16743
Reviewed-by: Frank Zago <fzago@cray.com>
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>