Include several fixies from upstream repo
    
    - Tighten hostname checks in legal hostname() function
    - Replace inet_addr() with inet_pton() in src/option.c
    - Use dnsmasq as default DNS server for RA only if it's doing DNS
    - Handle IPv4 interface address labels (aliases) in Linux (#962246)
    - Fix failure to start with ENOTSOCK (#962874)
    
    Signed-off-by: Tomas Hozza <thozza@redhat.com>