Fix "error: 'AV_HWDEVICE_TYPE_VAAPI' undeclared" in FFmpeg 2.8 - 3.x
Fix "error: 'AV_HWDEVICE_TYPE_VAAPI' undeclared" in FFmpeg 2.8 - 3.x

j-b-m/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt,j-b-m/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt