avfilter/af_flanger: free frame on ENOMEM

Signed-off-by: NKyle Swanson <k@ylo.ph>
Signed-off-by: NMichael Niedermayer <michael@niedermayer.cc>

libavfilter/af_flanger.c

@@ -149,8 +149,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
         out_frame = frame;
     } else {
         out_frame = ff_get_audio_buffer(inlink, frame->nb_samples);
-        if (!out_frame)
+        if (!out_frame) {
+            av_frame_free(&frame);
             return AVERROR(ENOMEM);
+        }
         av_frame_copy_props(out_frame, frame);
     }