LU-3544 fid: add a connect flag for open by FID

LU-3544 fid: add a connect flag for open by FID

Add OBD_CONNECT_OPEN_BY_FID for open by FID, if MDS supports this
, for open by FID, it won't retry with name if object with the FID
doesn't exist; while if client supports this, client won't pack name in
open request if FID is known.

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Change-Id: I158b96e8f55fe357b3542d320e894aeca18fca94
Reviewed-on: http://review.whamcloud.com/8093
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>