avformat/hlsenc: return media_url directly if failed to get seperator

Fix ticket: 8606
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

libavformat/hlsenc.c

@@ -1251,6 +1251,8 @@ static const char* get_relative_url(const char *master_url, const char *media_ur
             av_log(NULL, AV_LOG_WARNING, "Unable to find relative url\n");
             return NULL;
         }
+    } else {
+        return media_url;
     }
 
     return media_url + base_len + 1;