Merge remote-tracking branch 'qatar/master'

* qatar/master:
  af_join: do not leak input frames.
  asrc_anullsrc: return EOF, not -1

Conflicts:
	libavfilter/asrc_anullsrc.c

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

diff --cc libavfilter/af_join.c
Simple merge