Updates a set of agent settings.
If the argument "key" has the value "policy": updates the global agent settings. - See for agent setting names and values. - Zero or more of such settings can be specified. - If a setting isn't specified, its previous value is deleted. The corresponding default value will take the place of the previous value on the next call to . - See for restrictions on the values of the settings. - If at least one value is invalid, the entire set of settings is discarded.