Processor: pass context in and use it.
The processor used to create a new ConfigWriter when it was initialized. We now have one in the context, so we'll just recycle it. First of all we'll pass the context in when creating a new Processor object, then we'll just use context.cfg, which is granted to be initialized, wherever we used self.cfg, and stop checking whether the config is already initialized or not. In the future the Processor will be able to use the context also to acquire the BGL for LUs that require it, and to push the context down to LUs that don't in order for them to manage their own locking. Reviewed-by: iustinp