bigbuckbunny: Don't use whole avi in LIC_FILES_CHKSUM and add version

* it's causing huge deploy/licenses files:
  211M    deploy/licenses/bigbuckbunny-480p
  317M    deploy/licenses/bigbuckbunny-720p
  886M    deploy/licenses/bigbuckbunny-1080p
  and avi checksum is already verified by SRC_URI checksums

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>