Clean up conf's module_init()

Clean up conf's module_init()

Immediately error out when no name or value is passed instead of hiding
this in a a combination of ternary operator and strdup error check.
Use calloc(). Unindent some stupid, don't pretend this function can return
anything but -1 and 1, turn the whole thing into single exit and call the
now existing imodule_free() instead of handrolling it.

ok jsing