Description of problem:

If we configure ipaddr to be something like "ipaddr = radiusipv6.test.com" and 
radiusipv6.test.com points to ::1, radiusd tries to resolve the hostname to ipv4 address and fails with:
"Failed resolving "radiusipv6.test.com" to IPv4 address: Name or service not known"

radiusipv6.test.com resolves correctly with nslookup and dig:

Server:         127.0.0.1
Address:        127.0.0.1#53

Name:   radiusipv6.test.com
Address: ::1

$ dig radiusipv6.test.com ANY @127.0.0.1

; <<>> DiG 9.11.4-P2-RedHat-9.11.4-16.P2.el8 <<>> radiusipv6.test.com ANY @127.0.0.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4984
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: b6aea33c0406a5db47e36d9f5c7e6e3517a04cf1ad42adf9 (good)
;; QUESTION SECTION:
;radiusipv6.test.com.           IN      ANY

;; ANSWER SECTION:
radiusipv6.test.com.    86400   IN      AAAA    ::1

;; AUTHORITY SECTION:
test.com.               86400   IN      NS      dns1.test.com.

;; ADDITIONAL SECTION:
dns1.test.com.          86400   IN      A       127.0.0.1

;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Tue Mar 05 07:40:21 EST 2019
;; MSG SIZE  rcvd: 139


Version-Release number of selected component (if applicable):
freeradius-3.0.17-3.module+el8+2746+2e560403.x86_64
bind-9.11.4-16.P2.el8.x86_64

How reproducible:
Always

Steps to Reproduce:
1.Setup local bind server with a zone that contains something like "radiusipv6 IN  AAAA      ::1"
2.Configure the default site in sites-enabled to listen on this hostname with "ipaddr = radiusipv6.test.com"
3.run "radiusd -X"

Actual results:

radiusd: #### Loading Virtual Servers ####
server { # from file /etc/raddb/radiusd.conf
} # server
server default { # from file /etc/raddb/sites-enabled/default
 # Loading authenticate {...}
 # Loading authorize {...}
Ignoring "sql" (see raddb/mods-available/README.rst)
Ignoring "ldap" (see raddb/mods-available/README.rst)
 # Loading preacct {...}
 # Loading post-proxy {...}
 # Loading post-auth {...}
} # server default
radiusd: #### Opening IP addresses and Ports ####
listen {
        type = "auth"
Failed resolving "radiusipv6.test.com" to IPv4 address: Name or service not known


Expected results:
radiusd should start to listen on address ::1 port 1812 .

This is output from freeradius-3.0.15-18:

radiusd: #### Loading Virtual Servers ####
server { # from file /etc/raddb/radiusd.conf
} # server
server default { # from file /etc/raddb/sites-enabled/default
 # Loading authenticate {...}
 # Loading authorize {...}
Ignoring "sql" (see raddb/mods-available/README.rst)
Ignoring "ldap" (see raddb/mods-available/README.rst)
 # Loading preacct {...}
 # Loading post-proxy {...}
 # Loading post-auth {...}
} # server default
radiusd: #### Opening IP addresses and Ports ####
listen {
        type = "auth"
        ipaddr = radiusipv6.test.com IPv 6 address [::1]
        port = 0
   limit {
        max_connections = 16
        lifetime = 0
        idle_timeout = 30
   }
}
Listening on auth address ::1 port 1812 bound to server default
Listening on proxy address :: port 60405


Additional info:

relevant test: /CoreOS/freeradius/Sanity/check-ipaddr-ipv4addr-and-ipv6addr-address-usage