lavc/libxvid: fix mem leak in case of init failure

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavc/smvjpegdec: fix mem leak in case of init failure

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavc/huffyuvdec: fix mem leak in case of init failure

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
avutil/file: fix av_tempfile() documentation

Found-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>