Remove unused variable
Make CONF_PARSER dflt void*

As it's not always "char *"
Use talloc_free, not free()
Added paircompare_unregister_instance

which unregisters a paircompare() by module instance
Call paircompare_unregister_instance() when freeing modules

So that the modules don't have to do it themselves
Remove paircompare_unregister() from modules

They register using instance data, so the server core now
unregisters the paircompare's
Made userparse() readvp2() take TALLOC_CTX

so that the pairlist_free() code becomes simpler
The server core now calls xlat_unregister() for the modules