LU-15358 tests: Variable incorrectly defined in sanity-quota

LU-15358 tests: Variable incorrectly defined in sanity-quota

Under sanity-quota.sh local variable 'accnt_cnt' was
incorrectly defined. This was exposed using
shellcheck.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In ./lustre/tests/sanity-quota.sh line 3344:
local accnt_cnt
      ^-- SC2034: accnt_cnt appears unused. Verify it or export it.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Change-Id: Ib5971e7cc95b03c1f57411c6f02156ab236babcd
Test-Parameters: trivial testlist=sanity-quota
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-on: https://review.whamcloud.com/45820
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>