LU-4381 lov: to not hold sub locks at initialization

LU-4381 lov: to not hold sub locks at initialization

Otherwise, it will cause deadlock because it essentially holds
some sub locks and then to request others in an arbitrary order.

Lustre-commit: c6ab1fcc056778b18f685ec591ce27907e887617
Lustre-change: http://review.whamcloud.com/9152

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Change-Id: I9bdfa2339c83396efa5d16763a5329d06e232ddd
Reviewed-on: http://review.whamcloud.com/9994
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>