check if stream has been set, fixes CID15 RUN2

Originally committed as revision 13521 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffserver.c

@@ -3910,6 +3910,7 @@ static int parse_ffconfig(const char *filename)
             }
         } else if (!strcasecmp(cmd, "Format")) {
             get_arg(arg, sizeof(arg), &p);
+            if (stream) {
             if (!strcmp(arg, "status")) {
                 stream->stream_type = STREAM_TYPE_STATUS;
                 stream->fmt = NULL;
@@ -3929,6 +3930,7 @@ static int parse_ffconfig(const char *filename)
                 audio_id = stream->fmt->audio_codec;
                 video_id = stream->fmt->video_codec;
             }
+            }
         } else if (!strcasecmp(cmd, "InputFormat")) {
             get_arg(arg, sizeof(arg), &p);
             stream->ifmt = av_find_input_format(arg);