vaapi: don't unmap non-existing buffer

Some h264's can end up calling ff_vaapi_render_picture after a seek
with no buffer allocated and vaUnmapBuffer will assert on a invalid
buffer.
ffmpeg: add patch file for vaapi fix
ffmpeg: fixup compile error in patch
[AirPlay] - added missing ifdef checks for HAS_AIRPLAY and HAS_AIRTUNES
[language] - fix swedish short date format - thx to blittan