"ZOBS" (obsolete) tag and adds a "TDRC" tag at the end of the
list of tags using the first 4 characters of the "TYER" tag.
Since we write both the "TDRC" and "TYER" tags, the "TDRC" tag
will always be encountered first in the list. We want use it
since the converted "TYER" tag may have been truncated.
Refer to bugzilla for discussion, but, to summarize, this removes any writing of ID3V1 tags. ID3V1 tags will still be imported, but they will be written as ID3V2 tags.
