avconv: Simplify poll_filters() return value check

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

avconv.c

@@ -2556,17 +2556,13 @@ static int transcode(void)
         }
 
         ret = poll_filters();
-        if (ret < 0) {
-            if (ret == AVERROR_EOF || ret == AVERROR(EAGAIN)) {
-                continue;
-            } else {
+        if (ret < 0 && (ret != AVERROR_EOF || ret != AVERROR(EAGAIN))) {
             char errbuf[128];
             av_strerror(ret, errbuf, sizeof(errbuf));
 
             av_log(NULL, AV_LOG_ERROR, "Error while filtering: %s\n", errbuf);
             break;
         }
-        }
 
         /* dump report by using the output first video and audio streams */
         print_report(0, timer_start);