Merge commit '0b66fb45'

* commit '0b66fb45':
  flac_picture: prevent a possible out of bound write

This is only partly merged, the condition this checks for
is impossible to be true as it would imply avio_read() to
read more than the size passed to it

See: 731f7eaa
Merged-by: Michael Niedermayer <michaelni@gmx.at>