Merge commit '4e0be9c86f2003dd3ba2eb8fad01e8d0e538075e'

* commit '4e0be9c86f2003dd3ba2eb8fad01e8d0e538075e':
  vf_frei0r: prevent a segfault when filter parameters are not set

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

diff --cc libavfilter/vf_frei0r.c
Simple merge