server net: do proper cleanup on drop_con_finalize()

src/server/net.c

@@ -260,16 +260,12 @@ static void drop_con_finalize(struct con_data *c)
 		goto unlock;
 	}
 
-	if (!c->con) {
-		g_warning("c->con is NULL");
-		goto unlock;
-	}
-
-
+	if (c->con) {
 		if (G_IS_OBJECT(c->con)) {
 			g_warning("c->con still holds references");
 			goto unlock;
 		}
+	}
 
 	if (!c->nick) {
 		g_warning("double-free attempt");