LU-4610 tests: Turn on LFSCK debug messages

Turn on LFSCK debug messages by default in the
Lustre test framework.

Signed-off-by: James Nunez <james.a.nunez@intel.com>
Change-Id: I02490fafbe590fa226faa3b84f37f2c8b4736e5d
Reviewed-on: http://review.whamcloud.com/10814
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>