LU-3909 tests: sanity test 129 fix

Patch from LU-2479 changed max dir size limit behaviour. Before the
patch last block of a directory which reached its limit was mostly
empty so that creation of new file after limit cancelation caused no
dir size grow. With the patch last block of limited directory gets
full when limit is reached. Therefore dir size increases on file
creation after limit cancellation.
The patch makes sanity test_129 to distinguish these cases.

Xyratex-bug-id: MRP-1444
Signed-off-by: Vladmir Saveliev <vladimir_saveliev@xyratex.com>
Change-Id: I0ea9eee5a0d20f31d9f62e9e5f2af1ee550f3588
Reviewed-on: http://review.whamcloud.com/8143
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>