lavf/hlsenc: fix bogus hls segment index rewrapping logic

The counter should not be reset since it detects the
hls segment increasing timeframe.

Fixes ticket #2643.

Reviewed-by: Stefano Sabatini

libavformat/hlsenc.c

@@ -164,14 +164,12 @@ static int hls_start(AVFormatContext *s)
     AVFormatContext *oc = c->avf;
     int err = 0;
 
-    if (c->wrap)
-        c->number %= c->wrap;
-
     if (av_get_frame_filename(oc->filename, sizeof(oc->filename),
-                              c->basename, c->number++) < 0) {
+                              c->basename, c->wrap ? c->number % c->wrap : c->number) < 0) {
         av_log(oc, AV_LOG_ERROR, "Invalid segment filename template '%s'\n", c->basename);
         return AVERROR(EINVAL);
     }
+    c->number++;
 
     if ((err = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
                           &s->interrupt_callback, NULL)) < 0)