LU-3305 quota: avoid unnecessary dqget/dqput calls

LU-3305 quota: avoid unnecessary dqget/dqput calls

Because of the global lock contention inside the dqget()/dqput(),
we'd try to avoid dqget()/dqput() calls in dquot_initialize().

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: I4335d880f3b912f3de70816a9bd87841605f8907
Reviewed-on: http://review.whamcloud.com/6440
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>