randr: stop immutable output properties from being deleted (v2)

[Luc Verhaegen]

On Wed, Aug 24, 2011 at 12:19:58AM +0200, Luc Verhaegen wrote:
> 
> This version of the server side patch now no longer mangles the output
> properties list directly. This incurs a slight bit of overhead, in what is
> an extremely low frequency path anyway. It also fixes the error thrown in
> case the property does not exist for the listed output, to match
> QueryOutputProperty.
> 
> The new version of the randrproto.txt patch now fixes the two issues daniels
> spotted and now fully documents all the errors that RRDeleteOutputProperty
> might throw.
> 
> Luc Verhaegen.