Fixed a bug in tracknumber/duration code
Fixed a bug in tracknumber/duration code

reverendhomer/libmtp,kbhomes/libmtp-zune,libmtp/libmtp,philipl/libmtp,olunx/libmtp,kbhomes/libmtp-zune,jemc/libmtp,Bluerise/libmtp,philipl/libmtp,vmandela/libmtp,yifanlu/libMTP,libmtp/libmtp,pierrezurek/libmtp,olunx/libmtp,yifanlu/libMTP,olunx/libmtp,jemc/libmtp,Bluerise/libmtp,jemc/libmtp,reverendhomer/libmtp,pierrezurek/libmtp,mmalecki/libmtp,philipl/libmtp,vmandela/libmtp,jemc/libmtp,reverendhomer/libmtp,mmalecki/libmtp,Bluerise/libmtp,mmalecki/libmtp,libmtp/libmtp,reverendhomer/libmtp