The JPEG2000 encoder did not clean up after itself on error.
This commit fixes this by modifying the cleanup function to be able to
handle only partially allocated structures and by setting the
FF_CODEC_CAP_INIT_CLEANUP flag.
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>