Read CD audio USB drive bug fixed

libcdio seems to allow read no more than about 10 audio sectors at once when CD audio device is connected via USB.
This patch makes XBMC read small number of sectors if default one fails. It uses more CPU but allows to use USB CD devices.
Tested on GNU/Linux x86 and RPi. (On Rpi OMXPlayer does not play CD, but I can rip tracks).