[PATCH] implement print_modules()

[PATCH] implement print_modules()

From: Arjan van de Ven <arjanv@redhat.com>,
      Rusty Russell <rusty@rustcorp.com.au>

The patch below resolves the "Not Yet Implemented" print_modules() thing.
This is a really useful feature for distros; it allows us to do statistical
analysis on which modules are present how often in oopses compared to how
often they are used normally.  In addition it helps to spot candidates for
certain bugs without having to go back to the customer asking for this
information.