disable the hls_dispose by default to 0, for p2p system should never cleanup for timeshift hls.

@@ -624,8 +624,9 @@ vhost with-hls.srs.com {
         # the timeout in seconds to dispose the hls,
         # dispose is to remove all hls files, m3u8 and ts files.
         # when timeout or server terminate, dispose hls.
-        # default: 300
-        hls_dispose     300;
+        # @remark 0 to disable dispose.
+        # default: 0
+        hls_dispose     0;
         # the max size to notify hls,
         # to read max bytes from ts of specified cdn network,
         # @remark only used when on_hls_notify is config.

@@ -3566,7 +3566,7 @@ int SrsConfig::get_hls_dispose(string vhost)
 {
     SrsConfDirective* conf = get_hls(vhost);
     
-    int DEFAULT = 300;
+    int DEFAULT = 0;
     
     if (!conf) {
         return DEFAULT;

@@ -1155,6 +1155,14 @@ void SrsHls::dispose()
         on_unpublish();
     }
     
+    // only dispose hls when positive.
+    if (_req) {
+        int hls_dispose = _srs_config->get_hls_dispose(_req->vhost);
+        if (hls_dispose <= 0) {
+            return;
+        }
+    }
+    
     muxer->dispose();
 }