fix major fd leak in link handling

link_find_prioritized(): Properly close directory handles to fix a major fd
leak which caused hotplugging to fail entirely in many cases due to having too
many open files.

https://launchpad.net/bugs/463347

udev/udev-node.c

@@ -281,6 +281,7 @@ static const char *link_find_prioritized(struct udev_device *dev, bool add, cons
 			udev_device_unref(dev_db);
 		}
 	}
+	closedir(dir);
 	return target;
 }