Prevent crash on startup. Preliminary fix! I still need to actually reproduce original crash!
https://github.com/darktable-org/darktable/pull/548#issuecomment-42763922
Revert "Prevent crash on startup. Preliminary fix! I still need to actually reproduce original crash!"

This reverts commit f6129f8a352dd99037d98d5f8c51680ffb889ada.
Preset update infrastructure: some modules(e.g. lens iop) depend on global data in reload_defaults()

module->init(module); is already called by dt_iop_load_module_by_so()
Lens IOP: prevent crashes in legacy presets update infrastructure