On HUP, migrate the module configuration from the old CONF_SECTION

	On HUP, migrate the module configuration from the old CONF_SECTION
	to the new CONF_SECTION.  This means that (for example), sql doesn't
	have to tear down it's sockets & re-build them on HUP.  Instead,
	it just keeps working.

	The code is disabled (#if 0), because many modules depend on files
	on the disk, and they should re-read those on HUP, if they've
	changed.  This additional work requires:

	- flag in module_t saying "HUP-safe"
	- and the ability for modules to "register" files that they
	  depend, so that the HUP code can do the stat() itself, and
	  migrate the CONF_SECTION if nothing has changed