Revert r806010, which breaks mpm-itk.

See https://issues.apache.org/bugzilla/show_bug.cgi?id=52904 .

Index: httpd-2.4.1/include/ap_listen.h
===================================================================
--- httpd-2.4.1.orig/include/ap_listen.h
+++ httpd-2.4.1/include/ap_listen.h
@@ -96,11 +96,6 @@ AP_DECLARE(int) ap_setup_listeners(serve
  */
 AP_DECLARE_NONSTD(void) ap_close_listeners(void);
 
-/**
- * FIXMEDOC
- */
-AP_DECLARE_NONSTD(int) ap_close_selected_listeners(ap_slave_t *);
-
 /* Although these functions are exported from libmain, they are not really
  * public functions.  These functions are actually called while parsing the
  * config file, when one of the LISTEN_COMMANDS directives is read.  These
Index: httpd-2.4.1/server/listen.c
===================================================================
--- httpd-2.4.1.orig/server/listen.c
+++ httpd-2.4.1/server/listen.c
@@ -237,8 +237,7 @@ static apr_status_t close_listeners_on_e
 }
 
 static const char *alloc_listener(process_rec *process, char *addr,
-                                  apr_port_t port, const char* proto,
-                                  void *dummy)
+                                  apr_port_t port, const char* proto)
 {
     ap_listen_rec **walk, *last;
     apr_status_t status;
@@ -273,9 +272,6 @@ static const char *alloc_listener(proces
     }
 
     if (found_listener) {
-        if (ap_listeners->slave != dummy) {
-            return "Cannot define a slave on the same IP:port as a Listener";
-        }
         return NULL;
     }
 
@@ -333,7 +329,6 @@ static const char *alloc_listener(proces
             last->next = new;
             last = new;
         }
-        new->slave = dummy;
     }
 
     return NULL;
@@ -588,22 +583,6 @@ AP_DECLARE_NONSTD(void) ap_close_listene
         lr->active = 0;
     }
 }
-AP_DECLARE_NONSTD(int) ap_close_selected_listeners(ap_slave_t *slave)
-{
-    ap_listen_rec *lr;
-    int n = 0;
-
-    for (lr = ap_listeners; lr; lr = lr->next) {
-        if (lr->slave != slave) {
-            apr_socket_close(lr->sd);
-            lr->active = 0;
-        }
-        else {
-            ++n;
-        }
-    }
-    return n;
-}
 
 AP_DECLARE(void) ap_listen_pre_config(void)
 {
@@ -612,10 +591,7 @@ AP_DECLARE(void) ap_listen_pre_config(vo
     ap_listenbacklog = DEFAULT_LISTENBACKLOG;
 }
 
-/* Hack: populate an extra field
- * When this gets called from a Listen directive, dummy is null.
- * So we can use non-null dummy to pass a data pointer without conflict
- */
+
 AP_DECLARE_NONSTD(const char *) ap_set_listener(cmd_parms *cmd, void *dummy,
                                                 int argc, char *const argv[])
 {
@@ -662,7 +638,7 @@ AP_DECLARE_NONSTD(const char *) ap_set_l
         ap_str_tolower(proto);
     }
 
-    return alloc_listener(cmd->server->process, host, port, proto, dummy);
+    return alloc_listener(cmd->server->process, host, port, proto);
 }
 
 AP_DECLARE_NONSTD(const char *) ap_set_listenbacklog(cmd_parms *cmd,