kdump-lib.sh: introduce a helper to get all crypt dev used by kdump
    
    Resolves: bz1951415
    Upstream: fedora
    Conflict: None
    
    commit 1c70cf51c7678499e2d48eec10ad24b839fe9f64
    Author: Kairui Song <kasong@redhat.com>
    Date:   Tue May 18 16:13:16 2021 +0800
    
        kdump-lib.sh: introduce a helper to get all crypt dev used by kdump
    
        Signed-off-by: Kairui Song <kasong@redhat.com>
        Acked-by: Pingfan Liu <piliu@redhat.com>
    
    Signed-off-by: Kairui Song <kasong@redhat.com>