busybox DNS and profile Configuration

Busybox 支持解析功能，做法如下：在/etc 目录下做一个链接就可以 /etc/resolv.conf A symbolic link to /var/etc/resolv.conf so that the DNS information is stored in a RAM filesystem. If the system is not using DHCP to obtain this, then the link should be replaced with an actual file. 同时可以建立/etc/profile文件在init中会执行sh 从而会读取这个文件 并执行里面的内容，这样做比较清楚，免的加一个nod就去改simpleinit程序。