LU-6029 test: add wrap up duration in conf-sanity test_84

The time of execution the function target_finish_recovery() can be
very long but "obd->obd_recovery_end = cfs_time_current_sec();" set
at the end. Therefore the recovery time always will be more than
hard limit and depends how long target_finish_recovery() function
was executed.

To avoid instability in test_84 just add 5 seconds as wrap up time.

Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Change-Id: I53263f9a248429f59741f701fcc7b5b6d693325e
Reviewed-on: http://review.whamcloud.com/13087
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Sergey Cheremencev <sergey_cheremencev@xyratex.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>