LU-6298 hsm: shutdown HSM CDTs in parallel

In sanity-hsm.sh rewrite copytool_cleanup() to shutdown and restart
the MDT HSM coordinators in parallel. This saves about 8 * (MDSCOUNT -
1) seconds per call.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I75445ad126dc73251a3d056611133e3ab6b83362
Reviewed-on: http://review.whamcloud.com/13901
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>