BiBer: Remove "barcode" for reservations
(we have no field for it yet)
{
"Nr": null,
- "Mediennr": "barcode",
+ "Mediennr": null,
"\u00a0A\u00a0": null,
"Signatur / Kurztitel": "author+title",
"Vormerkung: Signatur / Kurztitel": "author+title",
