sanlock: renewal changes
    
    Remove the pthread cond var and cond_timedwait and
    replace with a much simpler sleep.  This seems to
    eliminates the erratic renewal behavior, in addition
    to making the code simpler.
    
    In the renewal thread, only use the leader timestamp
    when the renewal was successful.
    
    Add/change debugging messages related to renewls.
    
    Use local variables in renewal thread to guard against
    corrupting the disk if a bug causes the sp struct be
    corrupted.