Minor docs tweak: SECURITY_ENCRYPTOR

I've just noticed that in the docs it says:

AM Encryption Class
- This property does not apply to Java Agents 5.7, although it might appear in the AM console.

This isn't quite true. The property

com.iplanet.security.encryptor

which I have just now aliased to:

org.forgerock.agents.encryptor.classname

does apply to Agents 5.7 and all other versions of the Java Agent. However the property itself must be defined in the bootstrap properties file. If it is visible in the AM console at all, it will have no effect (it is needed on Agent startup, and retrieving it from AM comes too late in the cycle of things).

Also I have changed the default for this property to the classname for AESWrapEncyption which is a much more secure encryption algorithm than the largely defunct JCEEncryption class mentioned in the docs.