ff_flac_parse_picture: assert that len is within the array

The check that gurantees this isnt recognized by coverity for
example

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/oggparsevorbis: fix leak of ct

Fixes CID1061058
Fixes fate

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/oggparsevorbis: fix leak of tt

Fixes CID1061059
Fixes fate
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>