Fix UnboundLocalError for dhcp_addr in get_adapter_addresses

When a network adapter has DHCP_ENABLED and IPV6_ENABLED flags set
but not IPV4_ENABLED, the dhcp_addr variable is never assigned before
being referenced in the IPv6 check condition, causing:

  UnboundLocalError: cannot access local variable 'dhcp_addr'

This occurs on cloud VMs with vDPA/SR-IOV networking where the
adapter may have IPv6 link-local addressing (DHCP enabled) but
static IPv4 configuration (no IPV4_ENABLED flag).

Fix by initializing dhcp_addr to None before the conditional
assignments.

Signed-off-by: Max Makarov <maxpain@linux.com>

Author: maxpain

cloudbaseinit/utils/windows/network.py

@@ -120,6 +120,7 @@ def get_adapter_addresses():
 
                 if dhcp_enabled:
                     if not xp_data_only:
+                        dhcp_addr = None
                         if curr_addr.Flags & iphlpapi.IP_ADAPTER_IPV4_ENABLED:
                             dhcp_addr = curr_addr.Dhcpv4Server