tests: Fix cloudsigma tests when no dmidecode data is present.
The cloudsigma tests had few test cases that were not getting
all the "mocks" set up correctly. Specifically is_running_in_cloudsigma
was not getting replaced and calls would leack through to
util.read_dmi_data.
Add 'accept-ra: true|false' parameter to config v1 and
v2. When True: accept_ra is set to '1'. When False:
accept_ra is set to '0'. When not defined in config the
value is left to the operating system default.
This change also extend the IPv6 support to distinguish
between slaac and dhcpv6-stateless. SLAAC is autoconfig
without any options from DHCP, while stateless auto-configures
the address and the uses DHCP for other options.
Azure's Instance Metadata Service (IMDS) reports multiple IPv6
addresses, via the http://169.254.169.254/metadata/instance/network
route. Any additional values after the first in 'ipAddresses' under the
'ipv6' interface key are extracted and configured as static IPs on
the interface.
Fix metadata check when local-hostname is null (#32)
Fix traceback when running with a config drive containing a metadata file which has
local-hostname set to null. Cloud-init ignores absent local-hostname or None values.