Reference a public IPv4 that has a PTR record

Public IPv6 192.240.153.117 is managed by OVH US and has a PTR
117.153.240.192.in-addr.arp record that resolves to www.rabbitmq.com. It
would be nice to move to an IPv4 & IPv6 that are managed by our wider
org.

    dig 117.153.240.192.in-addr.arpa PTR +short
    www.rabbitmq.com.

    whois 192.240.153.117 | grep -i Organiz
    Organization:   OVH US LLC (OUL-16)

cc @michaelklishin @trevormarshall

Author: gerhard

test/peer_discovery_dns_SUITE.erl

@@ -49,13 +49,7 @@ suite() ->
 %% Testsuite setup/teardown.
 %% -------------------------------------------------------------------
 
-%% peer_discovery.tests.rabbitmq.net used in the tests below
-%% returns three A records two of which fail our resolution process:
-%%
-%% * One does not resolve to a [typically] non-reachable IP
-%% * One does not support reverse lookup queries
-
--define(DISCOVERY_ENDPOINT_RECORD_A, "peer_discovery.tests.rabbitmq.net").
+-define(DISCOVERY_ENDPOINT_RECORD_A, "peer_discovery.tests.ipv4.rabbitmq.com").
 
 -define(DISCOVERY_ENDPOINT_RECORD_AAAA, "www.v6.facebook.com").
 
@@ -78,7 +72,7 @@ init_per_testcase(test_aaaa_record, Config) ->
 init_per_testcase(_Testcase, Config) ->
     case inet_res:lookup(?DISCOVERY_ENDPOINT_RECORD_A, in, a) of
         []      ->
-            {skip, "pre-configured *.rabbitmq.net record does not resolve, skipping"};
+            {skip, "pre-configured *.rabbitmq.com record does not resolve, skipping"};
         [_ | _] ->
             Config
     end.
@@ -87,7 +81,7 @@ init_per_testcase(_Testcase, Config) ->
 end_per_testcase(_Testcase, Config) ->
     case inet_res:lookup(?DISCOVERY_ENDPOINT_RECORD_A, in, a) of
         []      ->
-            {skip, "pre-configured *.rabbitmq.net record does not resolve, skipping"};
+            {skip, "pre-configured *.rabbitmq.com record does not resolve, skipping"};
         [_ | _] ->
             Config
     end.