Closes the session.
Returns True if the session has been successfully closed and False if any error has occured.
Call this method to close current session to the token.
Note, that this method must not be used if you access the hardware device via TElPKCS11CertStorage or TElSSHPKCS11KeyStorage classes. Please use the CloseSession() method of the respective storage object to close the session properly, and release all the resources allocated for it.