ocfs2: Check the owner of a lockres inside the spinlock

The checking of lockres owner in dlm_update_lvb() is not inside spinlock
protection. I don't see problem in current call path of dlm_update_lvb().
But just for code robustness.

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>