initialized by flags (function argument) or-ed with ifa->ifa_flags.
If both NIC has a loopback route to itself, so IFA_RTSELF is set on ifa(s).
As IFA_RTSELF is defined by RTF_HOST, rtrequest1_fib() is called with
RTF_HOST flag even if netmask is not NULL. Consequently, netmask is set
to zero in rtrequest1_fib(), and request to add network route is changed
under hands to request to add host route.
Tested by: Andrew Boyer <aboyer at averesystems.com>
Submitted by: Svatopluk Kraus <onwahe at gmail dot com>
Approved by: re (hrs)
c7105822b4