totemip: Properly detect ipv6 address

Commit a853b618 introduced regression in finding IPv6 address. For IPv6,
IFA_ADDRESS must be checked, instead of IFA_LOCAL, because IFA_LOCAL is
returned empty.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Fabio M. Di Nitto <fdinitto@redhat.com>