copy the request for hls.

@@ -1117,6 +1117,7 @@ int SrsHlsCache::reap_segment(string log_desc, SrsHlsMuxer* muxer, int64_t segme
 
 SrsHls::SrsHls()
 {
+    _req = NULL;
     source = NULL;
     handler = NULL;
     
@@ -1137,6 +1138,7 @@ SrsHls::SrsHls()
 
 SrsHls::~SrsHls()
 {
+    srs_freep(_req);
     srs_freep(codec);
     srs_freep(sample);
     srs_freep(jitter);
@@ -1205,7 +1207,8 @@ int SrsHls::on_publish(SrsRequest* req)
 {
     int ret = ERROR_SUCCESS;
     
-    _req = req;
+    srs_freep(_req);
+    _req = req->copy();
     
     // update the hls time, for hls_dispose.
     last_update_time = srs_get_system_time_ms();