LU-7920 hsm: Account for decreasing max request count

LU-7920 hsm: Account for decreasing max request count

If HSM is active and the max request count is decreased, account for
that when checking to see if more requests should be started.

Signed-off-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Change-Id: I4dcf9ea192f9b354a9933e08d2ced9ced7b3bc7c
Reviewed-on: http://review.whamcloud.com/19382
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: Aurelien Degremont <aurelien.degremont@cea.fr>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>