Remove redundant options checks for IPv6 preference conflicts

It is no longer possible for the IPv6 preference options to differ from the
IPv6 usage: preferring IPv6 implies possibly using IPv6.

Also remove the corresponding unit test warning message checks.
(But keep the unit tests themselves - they now run without warnings.)

src/or/config.c

@@ -3305,23 +3305,6 @@ options_validate(or_options_t *old_options, or_options_t *options,
            "of the Internet, so they must not set Reachable*Addresses "
            "or FascistFirewall or FirewallPorts or ClientUseIPv4 0.");
 
-  /* We check if Reachable*Addresses blocks all addresses in
-   * parse_reachable_addresses(). */
-
-#define WARN_PLEASE_USE_IPV6_LOG_MSG \
-        "ClientPreferIPv6%sPort 1 is ignored unless tor is using IPv6. " \
-        "Please set ClientUseIPv6 1, ClientUseIPv4 0, or configure bridges."
-
-  if (!fascist_firewall_use_ipv6(options)
-      && options->ClientPreferIPv6ORPort == 1)
-    log_warn(LD_CONFIG, WARN_PLEASE_USE_IPV6_LOG_MSG, "OR");
-
-  if (!fascist_firewall_use_ipv6(options)
-      && options->ClientPreferIPv6DirPort == 1)
-    log_warn(LD_CONFIG, WARN_PLEASE_USE_IPV6_LOG_MSG, "Dir");
-
-#undef WARN_PLEASE_USE_IPV6_LOG_MSG
-
   if (options->UseBridges &&
       server_mode(options))
     REJECT("Servers must be able to freely connect to the rest "

src/test/test_options.c

@@ -1794,14 +1794,6 @@ test_options_validate__reachable_addresses(void *ignored)
 
   /* Test IPv4-only clients setting IPv6 preferences */
 
-#define WARN_PLEASE_USE_IPV6_OR_LOG_MSG \
-        "ClientPreferIPv6ORPort 1 is ignored unless tor is using IPv6. " \
-        "Please set ClientUseIPv6 1, ClientUseIPv4 0, or configure bridges.\n"
-
-#define WARN_PLEASE_USE_IPV6_DIR_LOG_MSG \
-        "ClientPreferIPv6DirPort 1 is ignored unless tor is using IPv6. " \
-        "Please set ClientUseIPv6 1, ClientUseIPv4 0, or configure bridges.\n"
-
   free_options_test_data(tdata);
   tdata = get_options_test_data(TEST_OPTIONS_DEFAULT_VALUES
                                 "ClientUseIPv4 1\n"
@@ -1811,7 +1803,6 @@ test_options_validate__reachable_addresses(void *ignored)
 
   ret = options_validate(tdata->old_opt, tdata->opt, tdata->def_opt, 0, &msg);
   tt_int_op(ret, OP_EQ, 0);
-  expect_log_msg(WARN_PLEASE_USE_IPV6_OR_LOG_MSG);
   tor_free(msg);
 
   free_options_test_data(tdata);
@@ -1823,7 +1814,6 @@ test_options_validate__reachable_addresses(void *ignored)
 
   ret = options_validate(tdata->old_opt, tdata->opt, tdata->def_opt, 0, &msg);
   tt_int_op(ret, OP_EQ, 0);
-  expect_log_msg(WARN_PLEASE_USE_IPV6_DIR_LOG_MSG);
   tor_free(msg);
 
   /* Now test an IPv4/IPv6 client setting IPv6 preferences */