sanlock: fix incorrect error from release
    
    In paxos release, check for different write_id first, rather
    than checking for different lver or owner first, because the
    different lver or owner is possible with a different write_id.
    When there is a write_id other than our own, setting the released
    flag in our dblock allows others to acquire the lease, and when
    we read the leader record, we can find that it's already held
    by another host.  This fix avoids returning an error from paxos
    release in this case.