HTTPLiveSource: fix non timed id3 track selection

Non timed id3 track selection generates INVALID_OPERATION when performed
on the last track.

The buggy logic reads:

if (not last track) {
  // non-timed-id3 related work
} else if (has timed id3) {
  // timed id3 related work
} // last track but non timed id3 not handled

It should read:

if (has no timed id3 || not last track) {
  // non-timed-id3 track related work
} else {
  // timed id3 related work
}

Bug: 21195284
Change-Id: I2ddb5d8e2a1ecba4cc071c7ee14c6697fe8e220d