When a new module that publishes questions is created, it does not have
a default question category created until it is viewed. This means that
other parts of the system that want to use the bank while its empty
(such as bulk moving questions) cannot see it.
This adds a step to the common edit_module_post_actions() function so
that any module supporting the FEATURE_PUBLISHES_QUESTIONS feature will
have its default category created with the module instance.
This can be overridden by setting skipdefaultcategory to true
in the $moduleinfo argument to edit_post_module_actions().
A multianswer question with a missing database record no longer throws
an exception, so doesn't work for the "broken question" test, so switch
to ddwtos.
Mihail Geshoski