Crash when the bitstream contains a CRA and following RASL pictures

[ChristianFeldmann]

When RASL pictures are encountered after a random access picture and this random access picture is the first one to be decoded, the decoder crashes. In this case the decoder should ignore the following RASL pictures. The bugfix fixes this issue but I am not 100% shure if there isn't a better way of doing this. I have a sample bitstream for this, unfortunately I cannot attach it here.