unregister_security — unregisters a security framework with the kernel
int unregister_security (struct security_operations * ops);
This function removes a struct security_operations variable that had
previously been registered with a successful call to register_security.
If ops does not match the valued previously passed to register_security
an error is returned. Otherwise the default security options is set to the
the dummy_security_ops structure, and 0 is returned.