LU-17871 ldlm: FLOCK ownlocks may be not set

LU-17871 ldlm: FLOCK ownlocks may be not set

Conflict checking loop should continue until ownlocks is set.
Ownlocks variable is essential for lock merges.

Lustre-change: https://review.whamcloud.com/55184
Lustre-commit: ede8d928d6c47551371512c80dfa4f159260e7e2

Fixes: b07a57027e (LU-15402 ldlm: speedup RD flock enqueue)
Signed-off-by: Sergey Cheremencev <scherementsev@ddn.com>
Signed-off-by: Andriy Skulysh <andriy.skulysh@hpe.com>
Change-Id: Ied526581dd7d4f100c95f2fe582d117a87a8a584
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/55246
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>