So that vlc --{list,help,module} don't get us a non-null exit code

(cherry picked from commit a2d82490555eb3271a77b4958bc8528091951901)

Conflicts:

	modules/control/rc.c

/!\ In pure C, `()` means `(...)`, not `(void)`

This reverts commit f3b97438.

It creates a circular reference holding. (playlist is the parent of the preparser and hold a reference to the preparser during all the preparser life's span).

(Not-So-Dumb-References-Checker IDentifier one)

I saw you, evil preparser thread...

If something depended on this behaviour, it should really be fixed...