mkdumprd: prompt the user to install nfs-utils when mounting NFS fs failed
    
    upstream: fedora
    resolves: bz2003832
    conflict: none
    
    commit e5a745ce776dd19d617c2025acb3e510585d4e82
    Author: Coiby Xu <coxu@redhat.com>
    Date:   Sat Feb 20 11:55:52 2021 +0800
    
        mkdumprd: prompt the user to install nfs-utils when mounting NFS fs failed
    
        When nfs-utils is not installed, mounting as NFS fs would fail.
        Currently, the error message is not user-friendly,
            mount: /tmp/mkdumprd.HyPGpS/target: bad option; for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount.<type> helper program.
            kdump: Failed to mount on xxx for kdump preflight check.
            kdump: mkdumprd: failed to make kdump initrd
    
        Prompt the user to install nfs-utilsa in the error message,
            kdump: Failed to mount on xxx for kdump preflight check. Please make sure nfs-utils has been installed.
    
        Signed-off-by: Coiby Xu <coxu@redhat.com>
        Acked-by: Kairui Song <kasong@redhat.com>
    
    Signed-off-by: Tao Liu <ltao@redhat.com>