If the last chunk had an odd size, the new chunk would have been written at
odd position, which is incorrect.
This is based on the patch by Jens Dyffort, but I ended up changing the
implementation to correctly handle subsequential updates to the file.
The whole RIFF code really needs to be rewritten in a different way...
BUG:243954
git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@1220223 283d02a7-25f6-0310-bc7c-ecb5cbfe19da