Deprecate ReachableDirAddresses and ClientPreferIPv6DirPort

Closes ticket 19704.

changes/ticket19704

+  o Deprecated features:
+    - The ReachableDirAddresses and ClientPreferIPv6DirPort options
+      are now deprecated; they do not apply to relays, and they
+      have had no effect on clients since 0.2.8.x. Closes ticket 19704.
+

doc/tor.1.txt

@@ -978,7 +978,8 @@ The following options are useful only for clients (that is, if
     these restrictions when fetching directory information, using standard HTTP
     GET requests. If not set explicitly then the value of
     **ReachableAddresses** is used. If **HTTPProxy** is set then these
-    connections will go through that proxy.
+    connections will go through that proxy.   (DEPRECATED: This option has
+    had no effect for some time.)
 
 [[ReachableORAddresses]] **ReachableORAddresses** __ADDR__[/__MASK__][:__PORT__]...::
     Like **ReachableAddresses**, a list of addresses and ports. Tor will obey
@@ -1547,7 +1548,8 @@ The following options are useful only for clients (that is, if
     server has both. (Tor also prefers an IPv6 DirPort if IPv4Client is set to
     0.) If this option is set to auto, clients prefer IPv4. Other things may
     influence the choice. This option breaks a tie to the favor of IPv6.
-    (Default: auto)
+    (Default: auto)  (DEPRECATED: This option has had no effect for some
+    time.)
 
 [[ClientPreferIPv6ORPort]] **ClientPreferIPv6ORPort** **0**|**1**|**auto**::
     If this option is set to 1, Tor prefers an OR port with an IPv6

src/or/config.c

@@ -693,6 +693,10 @@ static const config_deprecation_t option_deprecation_notes_[] = {
     "to your directory server, which your Tor probably wasn't using." },
   { "HTTPProxyAuthenticator", "HTTPProxy is deprecated in favor of HTTPSProxy "
     "which should be used with HTTPSProxyAuthenticator." },
+  { "ReachableDirAddresses", "It has no effect on relays, and has had no "
+    "effect on clients since 0.2.8." },
+  { "ClientPreferIPv6DirPort", "It has no effect on relays, and has had no "
+    "effect on clients since 0.2.8." },
   /* End of options deprecated since 0.3.2.0-alpha. */
 
   { NULL, NULL }