refactor use for loop to remove item from linked list

src/listener.c

@@ -51,27 +51,25 @@ listener_remove(notify notify_cb)
   struct listener *listener;
   struct listener *prev;
 
-  listener = listener_list;
   prev = NULL;
-
-  while (listener)
+  for (listener = listener_list; listener; listener = listener->next)
     {
       if (listener->notify_cb == notify_cb)
-	{
-	  if (prev)
-	    prev->next = listener->next;
-	  else
-	    listener_list = NULL;
-
-	  free(listener);
-	  return 0;
-	}
+	break;
 
       prev = listener;
-      listener = listener->next;
     }
 
-  return -1;
+  if (!listener)
+    return 0;
+
+  if (prev)
+    prev->next = listener->next;
+  else
+    listener_list = NULL;
+
+  free(listener);
+  return 0;
 }
 
 int