Bug#655365: ISRC code not stored

[jaakov at ro.ru]

Package: brasero
Version: 3.2.0-3
Severity: grave

Reproduce:
1. Create an audio project with some wav files.
2. Right-click on some file, choose "Edit Information...".
3. Enter some ISRC code, click the "Apply" button.
4. Right-click on the same file, choose "Edit Information...".
5. Observe that the ISRC field is empty.

Expected: The ISRC field is preserved.