How do I delete a symlink from /sbin?
Android devices have a unique way of booting, using a binary blob called boot.img that contains the kernel, and a ramdisk. This ramdisk will contain the /sbin symlink you want to remove.

To remove this, you will probably need either an upgrade image, or you will have to extract boot.img from your device. I can look for or put together instructions for this if you wish.

Once you have the extracted boot.img, you have to then extract the ramdisk image from it, make your changes, and put everything back together.

Then comes the dangerous part, unless you know you cannot brick your phone. You will need to flash this (hopefully working!) boot.img so that Android will use the new ramdisk.

So, for now, it might be better to figure out if there is an init script in the /system directory that you could remove your symlink in each time your phone starts.


  Update: or, like you did, you could just change the init script that calls swapon to call a different one.