Add ssh dump support
    
    Add ssh dump support
    
    changes including below items:
    1. sshkey option
    2. sshkey propagate
    3. fix a bug of  _server ip calculation for dump target string
    4. change the prefix of kdump hook from 93 to 01 to avoid dhclient and
       other cleanups happening before us
    5. enable network with dracut cmdline rd.neednet=1 when there's network
       target config
    
    [v1 - v2]:
    Only check_ssh_target when there's ssh dump target in kdump config file
    
    [v2 -> v3]
    style fixes: trailing spaces and space before tab indent
    remove set -x
    simply check_ssh_target
    use awk to get sshkey option value
    change pivot hook order to 0000
    
    Signed-off-by: Dave Young <dyoung@redhat.com>