coverity 11956 - Dereference after null check
    
    Fix description: The NULL check is if either (remote_subtree or
    local_subtree is NULL) and (subtree_pairs is NULL), then it bails.
    The location that Coverity reported is changed to "strictly"
    subtree_pairs is NULL.  That is, local_subtree cannot be NULL.
    
    I applied the fix to the similar places.
    
    Reviewed by Rich (Thank you!!)