avformat/movenchint: use av_freep() for safety

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
vcodec/rpza: print mismatching size in case of error

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/rpza: fix +- error

Fixes Ticket3471

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