src: Use device alias when ifname is unset in virDomainInterfaceAddresses()

src: Use device alias when ifname is unset in virDomainInterfaceAddresses()

The virDomainInterfaceAddresses() API returns an array of
_virDomainInterface structs which then describe IP addresses
associated with given domain. The struct contains 'name' member
which is documented deliberately vaguely: "interface name". This
is because depending on the source of truth used (controlled by
'source' argument) the name can be wildly different from the one
in domain XML. Now, in case of source =
VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_ARP, the host's ARP table is
parsed and matching interfaces are found by comparing MAC
addresses. If it's a match then the 'name' is set to net->ifname
(corresponds to /interface/target/@dev). But that is not always
set and sometimes may be NULL (e.g. for hostdevs, usernet). We
can't change the API (like we did for hwaddr in v1.2.14-rc1~105)
because this is already released. So the next best thing to do is
to put the interface alias in there.

To be on a safe side, do the same change to the
VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LEASE case.

Resolves: https://issues.redhat.com/browse/RHEL-141496
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>