Better resolv.conf parsing

  NET_OPTS="-netdev tap,ifname=${VM_NET_TAP},script=no,downscript=no,id=hostnet0"

  # Build DNS options from container /etc/resolv.conf

  mapfile -t nameservers < <(grep '^nameserver' /etc/resolv.conf | sed 's/nameserver //')

  searchdomains=$(grep '^search' /etc/resolv.conf | sed 's/search //' | sed 's/ /,/g')

  if [ "$DEBUG" = "Y" ]; then

    echo "/etc/resolv.conf:" && echo && cat /etc/resolv.conf && echo

  fi

  mapfile -t nameservers < <(grep '^nameserver' /etc/resolv.conf | sed 's/\t/ /g' | sed 's/nameserver //' | sed 's/ //g')

  searchdomains=$(grep '^search' /etc/resolv.conf | sed 's/\t/ /g' | sed 's/search //' | sed 's/#.*//' | sed 's/\s*$//g' | sed 's/ /,/g')

  domainname=$(echo "$searchdomains" | awk -F"," '{print $1}')

  for nameserver in "${nameservers[@]}"; do

    nameserver=$(echo "$nameserver" | sed 's/#.*//' )

    if ! [[ "$nameserver" =~ .*:.* ]]; then

      [[ -z "$DNS_SERVERS" ]] && DNS_SERVERS="$nameserver" || DNS_SERVERS="$DNS_SERVERS,$nameserver"

    fi