LU-10269 ldlm: fix the issues introduced by try bits

LU-10269 ldlm: fix the issues introduced by try bits

Try to grant optinal try_bits if lock is not blocked
and to be granted immediately otherwise trybits are cleared,
therefore there are no locks with trybits in both granted and
waiting queue.

Also mdt_object_lock_try() is changed to don't return negative for
try lock only case.

Test-Parameters: mdscount=1 mdtcount=1 testlist=racer,racer,racer
Signed-off-by: Mikhal Pershin <mike.pershin@intel.com>
Change-Id: If3f5734355511ad1af71d5996026d04c60f3e8c1
Reviewed-on: https://review.whamcloud.com/30246
Tested-by: Jenkins
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>