Fix ID3v2::UniqueFileIdentifier frame parsing.

According to the spec, the identifier contains arbitrary binary data (which
includes \0). That means splitting it on \0 and checking if we have only
two parts is wrong, because it rejects valid frames.


git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@735109 283d02a7-25f6-0310-bc7c-ecb5cbfe19da