LU-5807 qos: enable QOS_DEBUG()

LU-5807 qos: enable QOS_DEBUG()

Enable QOS_DEBUG() by default.

Lustre-commit: 24f49b88cfefcd748902a6056dfd8ce20bdd6b7f
Lustre-change: http://review.whamcloud.com/12434

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: If2b0e1388a5f12edd5b03ffc1081709b9efb1c13
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-on: http://review.whamcloud.com/12651
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>