bfi: check return value of av_malloc()

Signed-off-by: Paul B Mahol <onemda@gmail.com>
idcin: check return value of av_malloc()

Signed-off-by: Paul B Mahol <onemda@gmail.com>
westwood_vqa: check return value of av_malloc()

Signed-off-by: Paul B Mahol <onemda@gmail.com>
rmdec: Pass AVIOContext to rm_read_metadata()

Fix null pointer dereference
Fixes Ticket2588

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>