kdump-lib: fix typo in variable name
    
    Resolves: bz2076425
    Upstream: Fedora
    Conflict: None
    
    commit aa9bb8f8cef734fb1f6ab36ccaaa8936edb4f467
    Author: Philipp Rudo <prudo@redhat.com>
    Date:   Fri Mar 25 15:46:59 2022 +0100
    
        kdump-lib: fix typo in variable name
    
        in prepare_kdump_bootinfo s/defaut/default/.
    
        While at it declare it with the other local variables as local.
    
        Signed-off-by: Philipp Rudo <prudo@redhat.com>
        Reviewed-by: Tao Liu <ltao@redhat.com>
        Reviewed-by: Coiby Xu <coxu@redhat.com>
    
    Signed-off-by: Lichen Liu <lichliu@redhat.com>