Don't panic prematurely on a missing size (#1154190)
    
    Resolves: fed#1154190
    
    It might still be possible to obtain a size if the recommended flag is
    set and the logvol's mountpoint is "swap".
    
    Make logvol and partition code match, as much as possible.
    
    Signed-off-by: mulhern <amulhern@redhat.com>