Also, if fsCharsetToUtf8 can't convert to valid UTF-8, then don't add
it to the db, this way clients don't have to worry about weirdness and it
will force ppl to convert it.

git-svn-id: https://svn.musicpd.org/mpd/trunk@711 09075e82-0dd4-0310-85a5-a0d7c8717e4f