network-legacy/ifup: dhclient should be started in oneshot mode
    
    since we handle the retries explicitly via rd.net.dhcp.retry
    
    Without -1 if user sets ip=dhcp6 and there is no dhcp on the network,
    dhclient seems to wait indefinitely, ignoring rd.net.timeout.dhcp
    
    (cherry picked from commit 2181c80c91f05bfae5e50de2f502e363b0219bae)
    
    Resolves: #1787620
    
    patch_name: 0061.patch
    present_in_specfile: true
    location_in_specfile: 61
    squash_commits: true