totemip: compare sin6_scope_id and interface_num

When user configure a specific interface like vlan
with the same IPv6 link-local address, Corosync should
compare sin6_scope_id with interface_num, to make sure got
the right interface to bind

Signed-off-by: liangxin1300 <XLiang@suse.com>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>