Added a 'critical' argument to module configs

[Stef Walter]

Hi all,

Just a heads up that I've added a 'critical' argument to p11-kit module 
configs.

Previously if any module failed to initialize, then we would abort 
initialization of the registered modules. This was fragile and irritating.

I've changed it around so that specific modules can be marked critical 
with a 'critical: yes' in their configs. This can be specified in the 
system or user module config. If a module that is critical fails to 
initialize, then the entire initialization process will be aborted.

Modules are not critical by default.

Example here: 
http://p11-glue.freedesktop.org/doc/p11-kit/config-example.html

Documented here: 
http://p11-glue.freedesktop.org/doc/p11-kit/config-module.html

Does that sound good?

Stef