Rename `wait_for_dnsmasq_startup` to `wait_for_server_startup` and move
this function to test-common. Let this function take parameters to not
contain any dnsmasq specific code.
configure_networking: Configure IPv4 or IPv6 based on iBFT IP address
iSCSI Boot Firmware Table (iBFT) can provide the network configuration
that is needed to boot over iSCSI. The iBFT can contain IPv4 or IPv6
addresses. local-top/iscsi calls `configure_networking`. The default
behaviour of `configure_networking` is DHCPv4 on all available
interfaces (if ip= and ip6= are not set). If iBFT provides IPv6
addresses and no DHCPv4 server are running, `configure_networking` will
only try DHCPv4 and run into a timeout.
Placing the single line "ISCSI_AUTO=true" into
/etc/iscsi/iscsi.initramfs, or use the kernel boot line option
"iscsi_auto" will configure the network devices based on iBFT, but the
code in `local-top/iscsi` will assume that the addresses are IPv4.
If neither `ip=` nor `ip6=` are specified on the kernel cmdline, set the
`IP` and `IP6` parameter for `configure_networking` based on the IP
address provided by iBFT.
