Publisher is not sending 3rd layer in simulcast mode

[vpoddubchak]

Steps to reproduce:

1. Deploy and run licode in docker container
2. Modify BasicExample to use simulcast
3. Change settings to use defaultBW=3000, maxBandwidth=10000
4. Run it in 2 tabs and see webrtc-internals

In statistic on publisher side, we can see (see attach):
googFrameHeightInput: 480
googFrameHeightSent: 240
bitsSentPerSecond: ~1Mbit (far from maximum value, so, there is a room for more layers)

If deploy ackuaria and see on statistic of publisher's stream, we can see just 2 spatial layers (should be 3)