- Don't do extra dget() when creating symlink. 
This is a long-standing bug with a simple and obvious fix. We were doing 
an extra dget() on the dentry after d_instantiate(). It only gets decremented
once on removal, so the dentry was never really going away, and the directory
wasn't, either. 

- Use simple_unlink() instead of sysfs_unlink().

- Use simple_rmdir() instead of our own, unrolled, version. 

- Remove MODULE_LICENSE(), since it's always in the kernel.