Log: fencer: don't log assertion if unable to create full request reply
    
    Previously, we would log an assertion and a warning if asked to create a reply
    to a NULL request. However there is a possible sequence for this to happen:
    
    - Some nodes are up and some down at cluster start-up
    - One node is elected DC and schedules fencing of the down nodes
    - Fencing is initiated for one of the down nodes
    - One of the other down nodes comes up and is elected DC
    - The fencing result comes back and all peers (including new DC) are notified
    - New DC tries to create a notification for its client (the controller)
      but doesn't know anything about the initial request
    
    For now, just log a warning and drop the assertion. Longer term, maybe we
    should synchronize in-flight request information when a fencer joins the
    process group.
    
    patch_name: 011-cts.patch
    present_in_specfile: true
    location_in_specfile: 11
    squash_commits: true