LU-3976 tests: sanity-hsm test_9a is buggy

LU-3976 tests: sanity-hsm test_9a is buggy

After a file is successfully archived, it's HSM status is
EXIST and ARCHIVED so 0x00000009
Also add a generic function to test the minimum count of clients
needed by a test

Test-Parameters: clientcount=4
Signed-off-by: JC Lafoucriere <jacques-charles.lafoucriere@cea.fr>
Change-Id: I878e994d1a903646adc1c55e706ea9118196c0a1
Reviewed-on: http://review.whamcloud.com/7723
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>