LU-4093 tests: fix typo and inverted test in original patch

LU-4093 tests: fix typo and inverted test in original patch

1st/original patch for LU-4093 ticket, patch-set #3 of Change at
http://review.whamcloud.com/8157/ with Id
I3274e5864469251e6f2040377b84429e4f218f47, contains a typo and
an inverted test that prevent it to work as expected but rather
with reversed logic.

Signed-off-by: Bruno Faccini <bruno.faccini@intel.com>
Change-Id: I3f8031b85db116711312b8f7decf2c33761b89e6
Reviewed-on: http://review.whamcloud.com/8329
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>