Remove unsupported libcue from package mpd

Support for libcue has been removed for mpd since version 0.17.

Signed-off-by: Jörg Krause <jkrause@posteo.de>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>