audio/easytag: fix vorbis file corruption

Tagging vorbis files with EasyTag results in corrupted files, as reported in
https://bugzilla.gnome.org/show_bug.cgi?id=776110. Apply a fix from
https://build.opensuse.org/request/show/596947 to overcome the issue.

Reported by: tj@mrsk.me
Obtained from: openSUSE