mkdumprd: Improve error messages on non-existing NFS target directories
    
    Resolves: bz2090534
    Upstream: Fedora
    Conflict: None
    
    commit 4d52b7d5480ae27bfe70a55030b3be1282843662
    Author: Lichen Liu <lichliu@redhat.com>
    Date:   Tue Sep 6 11:15:15 2022 +0800
    
        mkdumprd: Improve error messages on non-existing NFS target directories
    
        When kdump is configured with a NFS location, and the remote directory does
        not exist, kdump.service fails with a confusing error message.
    
            kdumpctl[2172]: kdump: Dump path "/tmp/mkdumprd.ftWhOF/target/dumps"
            does not exist in dump target "10.111.113.2:/srv/kdump"
    
        We just need to print the remote directory "dumps" in such case, because
        "/tmp/mkdumprd.ftWhOF/target" is the local temporary mount point.
    
        Signed-off-by: Lichen Liu <lichliu@redhat.com>
        Reviewed-by: Coiby Xu<coxu@redhat.com>
    
    Signed-off-by: Lichen Liu <lichliu@redhat.com>