LU-5986 test: fix conflicting conf-sanity 83 test.

Patches for both LU-4119 and LU-5729 introduced test
83 to conf-sanity. The simple fix is to renumber the
test from LU-4119 to test 84.

Change-Id: Idca7c97daface6768a08f7ef7cbd00b601921a1e
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Reviewed-on: http://review.whamcloud.com/12984
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>